blob: cf5b99e1f12b087cbed6831530175bc2c42d2928 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Christoph Hellwigd2852032014-01-17 12:06:53 +01002 * Copyright (C) 1999 Eric Youngdale
3 * Copyright (C) 2014 Christoph Hellwig
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 *
5 * SCSI queueing library.
6 * Initial versions: Eric Youngdale (eric@andante.org).
7 * Based upon conversations with large numbers
8 * of people at Linux Expo.
9 */
10
11#include <linux/bio.h>
James Bottomleyd3f46f32008-01-15 11:11:46 -060012#include <linux/bitops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/blkdev.h>
14#include <linux/completion.h>
15#include <linux/kernel.h>
Paul Gortmaker09703662011-05-27 09:37:25 -040016#include <linux/export.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/mempool.h>
18#include <linux/slab.h>
19#include <linux/init.h>
20#include <linux/pci.h>
21#include <linux/delay.h>
James Bottomleyfaead262006-02-14 10:42:07 -060022#include <linux/hardirq.h>
Jens Axboec6132da2007-10-16 11:08:49 +020023#include <linux/scatterlist.h>
Christoph Hellwigd2852032014-01-17 12:06:53 +010024#include <linux/blk-mq.h>
Hannes Reineckef1569ff2014-10-24 14:27:07 +020025#include <linux/ratelimit.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026
27#include <scsi/scsi.h>
Christoph Hellwigbeb40482006-06-10 18:01:03 +020028#include <scsi/scsi_cmnd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070029#include <scsi/scsi_dbg.h>
30#include <scsi/scsi_device.h>
31#include <scsi/scsi_driver.h>
32#include <scsi/scsi_eh.h>
33#include <scsi/scsi_host.h>
Christoph Hellwigee14c672015-08-27 14:16:59 +020034#include <scsi/scsi_dh.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
Christoph Hellwig3b5382c2014-05-06 12:25:40 +020036#include <trace/events/scsi.h>
37
Linus Torvalds1da177e2005-04-16 15:20:36 -070038#include "scsi_priv.h"
39#include "scsi_logging.h"
40
41
Tobias Klauser6391a112006-06-08 22:23:48 -070042#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
Jens Axboe59725112007-04-02 10:06:42 +020043#define SG_MEMPOOL_SIZE 2
Linus Torvalds1da177e2005-04-16 15:20:36 -070044
45struct scsi_host_sg_pool {
46 size_t size;
Jens Axboea8474ce2007-08-07 09:02:51 +020047 char *name;
Christoph Lametere18b8902006-12-06 20:33:20 -080048 struct kmem_cache *slab;
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 mempool_t *pool;
50};
51
Mark Rustad037e6d82014-10-14 06:38:53 -070052#define SP(x) { .size = x, "sgpool-" __stringify(x) }
James Bottomleyd3f46f32008-01-15 11:11:46 -060053#if (SCSI_MAX_SG_SEGMENTS < 32)
54#error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater)
55#endif
Adrian Bunk52c1da32005-06-23 22:05:33 -070056static struct scsi_host_sg_pool scsi_sg_pools[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 SP(8),
58 SP(16),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020059#if (SCSI_MAX_SG_SEGMENTS > 32)
James Bottomleyd3f46f32008-01-15 11:11:46 -060060 SP(32),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020061#if (SCSI_MAX_SG_SEGMENTS > 64)
James Bottomleyd3f46f32008-01-15 11:11:46 -060062 SP(64),
63#if (SCSI_MAX_SG_SEGMENTS > 128)
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 SP(128),
James Bottomleyd3f46f32008-01-15 11:11:46 -060065#if (SCSI_MAX_SG_SEGMENTS > 256)
66#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020067#endif
68#endif
69#endif
James Bottomleyd3f46f32008-01-15 11:11:46 -060070#endif
71 SP(SCSI_MAX_SG_SEGMENTS)
Jens Axboea8474ce2007-08-07 09:02:51 +020072};
Linus Torvalds1da177e2005-04-16 15:20:36 -070073#undef SP
74
Martin K. Petersen7027ad72008-07-17 17:08:48 -040075struct kmem_cache *scsi_sdb_cache;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +020076
Jens Axboea488e742010-04-16 21:13:15 +020077/*
78 * When to reinvoke queueing after a resource shortage. It's 3 msecs to
79 * not change behaviour from the previous unplug mechanism, experimentation
80 * may prove this needs changing.
81 */
82#define SCSI_QUEUE_DELAY 3
83
Christoph Hellwigde3e8bf2014-01-23 13:55:38 +010084static void
85scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
Linus Torvalds1da177e2005-04-16 15:20:36 -070086{
87 struct Scsi_Host *host = cmd->device->host;
88 struct scsi_device *device = cmd->device;
Mike Christief0c0a372008-08-17 15:24:38 -050089 struct scsi_target *starget = scsi_target(device);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090
91 /*
Tejun Heo d8c37e72005-05-14 00:46:08 +090092 * Set the appropriate busy bit for the device/host.
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 *
94 * If the host/device isn't busy, assume that something actually
95 * completed, and that we should be able to queue a command now.
96 *
97 * Note that the prior mid-layer assumption that any host could
98 * always queue at least one command is now broken. The mid-layer
99 * will implement a user specifiable stall (see
100 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
101 * if a command is requeued with no other commands outstanding
102 * either for the device or for the host.
103 */
Mike Christief0c0a372008-08-17 15:24:38 -0500104 switch (reason) {
105 case SCSI_MLQUEUE_HOST_BUSY:
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100106 atomic_set(&host->host_blocked, host->max_host_blocked);
Mike Christief0c0a372008-08-17 15:24:38 -0500107 break;
108 case SCSI_MLQUEUE_DEVICE_BUSY:
James Smart573e5912011-07-06 12:45:17 -0400109 case SCSI_MLQUEUE_EH_RETRY:
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100110 atomic_set(&device->device_blocked,
111 device->max_device_blocked);
Mike Christief0c0a372008-08-17 15:24:38 -0500112 break;
113 case SCSI_MLQUEUE_TARGET_BUSY:
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100114 atomic_set(&starget->target_blocked,
115 starget->max_target_blocked);
Mike Christief0c0a372008-08-17 15:24:38 -0500116 break;
117 }
Christoph Hellwigde3e8bf2014-01-23 13:55:38 +0100118}
119
Christoph Hellwigd2852032014-01-17 12:06:53 +0100120static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
121{
122 struct scsi_device *sdev = cmd->device;
123 struct request_queue *q = cmd->request->q;
124
125 blk_mq_requeue_request(cmd->request);
126 blk_mq_kick_requeue_list(q);
127 put_device(&sdev->sdev_gendev);
128}
129
Christoph Hellwigde3e8bf2014-01-23 13:55:38 +0100130/**
131 * __scsi_queue_insert - private queue insertion
132 * @cmd: The SCSI command being requeued
133 * @reason: The reason for the requeue
134 * @unbusy: Whether the queue should be unbusied
135 *
136 * This is a private queue insertion. The public interface
137 * scsi_queue_insert() always assumes the queue should be unbusied
138 * because it's always called before the completion. This function is
139 * for a requeue after completion, which should only occur in this
140 * file.
141 */
142static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
143{
144 struct scsi_device *device = cmd->device;
145 struct request_queue *q = device->request_queue;
146 unsigned long flags;
147
148 SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
149 "Inserting command %p into mlqueue\n", cmd));
150
151 scsi_set_blocked(cmd, reason);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152
153 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 * Decrement the counters, since these commands are no longer
155 * active on the host/device.
156 */
James Bottomley4f5299a2009-01-02 10:42:21 -0600157 if (unbusy)
158 scsi_device_unbusy(device);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159
160 /*
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500161 * Requeue this command. It will go before all other commands
Bart Van Asscheb4854622012-06-29 15:36:07 +0000162 * that are already in the queue. Schedule requeue work under
163 * lock such that the kblockd_schedule_work() call happens
164 * before blk_cleanup_queue() finishes.
Jens Axboea488e742010-04-16 21:13:15 +0200165 */
Alan Stern644373a2014-03-28 10:51:15 -0700166 cmd->result = 0;
Christoph Hellwigd2852032014-01-17 12:06:53 +0100167 if (q->mq_ops) {
168 scsi_mq_requeue_cmd(cmd);
169 return;
170 }
Tejun Heo a1bf9d1d2005-04-24 02:08:52 -0500171 spin_lock_irqsave(q->queue_lock, flags);
James Bottomley59897da2005-09-14 12:57:42 -0400172 blk_requeue_request(q, cmd->request);
Jens Axboe59c3d452014-04-08 09:15:35 -0600173 kblockd_schedule_work(&device->requeue_work);
Bart Van Asscheb4854622012-06-29 15:36:07 +0000174 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175}
176
James Bottomley4f5299a2009-01-02 10:42:21 -0600177/*
178 * Function: scsi_queue_insert()
179 *
180 * Purpose: Insert a command in the midlevel queue.
181 *
182 * Arguments: cmd - command that we are adding to queue.
183 * reason - why we are inserting command to queue.
184 *
185 * Lock status: Assumed that lock is not held upon entry.
186 *
187 * Returns: Nothing.
188 *
189 * Notes: We do this for one of two cases. Either the host is busy
190 * and it cannot accept any more commands for the time being,
191 * or the device returned QUEUE_FULL and can accept no more
192 * commands.
193 * Notes: This could be called either from an interrupt context or a
194 * normal process context.
195 */
Bart Van Assche84feb162012-06-29 15:35:05 +0000196void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
James Bottomley4f5299a2009-01-02 10:42:21 -0600197{
Bart Van Assche84feb162012-06-29 15:35:05 +0000198 __scsi_queue_insert(cmd, reason, 1);
James Bottomley4f5299a2009-01-02 10:42:21 -0600199}
James Bottomley39216032005-06-15 18:48:29 -0500200/**
James Bottomley33aa6872005-08-28 11:31:14 -0500201 * scsi_execute - insert request and wait for the result
James Bottomley39216032005-06-15 18:48:29 -0500202 * @sdev: scsi device
203 * @cmd: scsi command
204 * @data_direction: data direction
205 * @buffer: data buffer
206 * @bufflen: len of buffer
207 * @sense: optional sense buffer
208 * @timeout: request timeout in seconds
209 * @retries: number of times to retry request
James Bottomley33aa6872005-08-28 11:31:14 -0500210 * @flags: or into request flags;
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900211 * @resid: optional residual length
James Bottomley39216032005-06-15 18:48:29 -0500212 *
Michael Opdenacker59c51592007-05-09 08:57:56 +0200213 * returns the req->errors value which is the scsi_cmnd result
James Bottomleyea73a9f2005-08-28 11:33:52 -0500214 * field.
Rob Landleyeb448202007-11-03 13:30:39 -0500215 */
James Bottomley33aa6872005-08-28 11:31:14 -0500216int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
217 int data_direction, void *buffer, unsigned bufflen,
Martin K. Petersen2bfad212014-04-09 22:20:48 -0400218 unsigned char *sense, int timeout, int retries, u64 flags,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900219 int *resid)
James Bottomley39216032005-06-15 18:48:29 -0500220{
221 struct request *req;
222 int write = (data_direction == DMA_TO_DEVICE);
223 int ret = DRIVER_ERROR << 24;
224
Mel Gorman71baba42015-11-06 16:28:28 -0800225 req = blk_get_request(sdev->request_queue, write, __GFP_RECLAIM);
Joe Lawrencea492f072014-08-28 08:15:21 -0600226 if (IS_ERR(req))
James Bottomleybfe159a2011-07-07 15:45:40 -0500227 return ret;
Jens Axboef27b0872014-06-06 07:57:37 -0600228 blk_rq_set_block_pc(req);
James Bottomley39216032005-06-15 18:48:29 -0500229
230 if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
Mel Gorman71baba42015-11-06 16:28:28 -0800231 buffer, bufflen, __GFP_RECLAIM))
James Bottomley39216032005-06-15 18:48:29 -0500232 goto out;
233
234 req->cmd_len = COMMAND_SIZE(cmd[0]);
235 memcpy(req->cmd, cmd, req->cmd_len);
236 req->sense = sense;
237 req->sense_len = 0;
Mike Christie17e01f22005-11-11 05:31:37 -0600238 req->retries = retries;
James Bottomley39216032005-06-15 18:48:29 -0500239 req->timeout = timeout;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200240 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
James Bottomley39216032005-06-15 18:48:29 -0500241
242 /*
243 * head injection *required* here otherwise quiesce won't work
244 */
245 blk_execute_rq(req->q, NULL, req, 1);
246
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400247 /*
248 * Some devices (USB mass-storage in particular) may transfer
249 * garbage data together with a residue indicating that the data
250 * is invalid. Prevent the garbage from being misinterpreted
251 * and prevent security leaks by zeroing out the excess data.
252 */
Tejun Heoc3a4d782009-05-07 22:24:37 +0900253 if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen))
254 memset(buffer + (bufflen - req->resid_len), 0, req->resid_len);
Alan Sternbdb2b8c2008-06-24 14:03:14 -0400255
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900256 if (resid)
Tejun Heoc3a4d782009-05-07 22:24:37 +0900257 *resid = req->resid_len;
James Bottomley39216032005-06-15 18:48:29 -0500258 ret = req->errors;
259 out:
260 blk_put_request(req);
261
262 return ret;
263}
James Bottomley33aa6872005-08-28 11:31:14 -0500264EXPORT_SYMBOL(scsi_execute);
James Bottomley39216032005-06-15 18:48:29 -0500265
Lin Ming9b214932013-03-23 11:42:25 +0800266int scsi_execute_req_flags(struct scsi_device *sdev, const unsigned char *cmd,
James Bottomleyea73a9f2005-08-28 11:33:52 -0500267 int data_direction, void *buffer, unsigned bufflen,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +0900268 struct scsi_sense_hdr *sshdr, int timeout, int retries,
Martin K. Petersen2bfad212014-04-09 22:20:48 -0400269 int *resid, u64 flags)
James Bottomleyea73a9f2005-08-28 11:33:52 -0500270{
271 char *sense = NULL;
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700272 int result;
273
James Bottomleyea73a9f2005-08-28 11:33:52 -0500274 if (sshdr) {
Jes Sorensen24669f752006-01-16 10:31:18 -0500275 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500276 if (!sense)
277 return DRIVER_ERROR << 24;
James Bottomleyea73a9f2005-08-28 11:33:52 -0500278 }
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700279 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
Lin Ming9b214932013-03-23 11:42:25 +0800280 sense, timeout, retries, flags, resid);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500281 if (sshdr)
James Bottomleye5143852005-08-09 11:55:36 -0500282 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500283
284 kfree(sense);
285 return result;
286}
Lin Ming9b214932013-03-23 11:42:25 +0800287EXPORT_SYMBOL(scsi_execute_req_flags);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500288
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289/*
290 * Function: scsi_init_cmd_errh()
291 *
292 * Purpose: Initialize cmd fields related to error handling.
293 *
294 * Arguments: cmd - command that is ready to be queued.
295 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296 * Notes: This function has the job of initializing a number of
297 * fields related to error handling. Typically this will
298 * be called once for each command, as required.
299 */
Christoph Hellwig631c2282006-07-08 20:42:15 +0200300static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302 cmd->serial_number = 0;
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200303 scsi_set_resid(cmd, 0);
FUJITA Tomonorib80ca4f2008-01-13 15:46:13 +0900304 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 if (cmd->cmd_len == 0)
Boaz Harroshdb4742d2008-04-30 11:27:26 +0300306 cmd->cmd_len = scsi_command_size(cmd->cmnd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307}
308
309void scsi_device_unbusy(struct scsi_device *sdev)
310{
311 struct Scsi_Host *shost = sdev->host;
Mike Christief0c0a372008-08-17 15:24:38 -0500312 struct scsi_target *starget = scsi_target(sdev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 unsigned long flags;
314
Christoph Hellwig74665012014-01-22 15:29:29 +0100315 atomic_dec(&shost->host_busy);
Christoph Hellwig2ccbb002014-03-26 10:35:00 +0100316 if (starget->can_queue > 0)
317 atomic_dec(&starget->target_busy);
Christoph Hellwig74665012014-01-22 15:29:29 +0100318
James Bottomley939647e2005-09-18 15:05:20 -0500319 if (unlikely(scsi_host_in_recovery(shost) &&
Christoph Hellwig74665012014-01-22 15:29:29 +0100320 (shost->host_failed || shost->host_eh_scheduled))) {
321 spin_lock_irqsave(shost->host_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 scsi_eh_wakeup(shost);
Christoph Hellwig74665012014-01-22 15:29:29 +0100323 spin_unlock_irqrestore(shost->host_lock, flags);
324 }
325
Christoph Hellwig71e75c92014-04-11 19:07:01 +0200326 atomic_dec(&sdev->device_busy);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327}
328
Christoph Hellwigd2852032014-01-17 12:06:53 +0100329static void scsi_kick_queue(struct request_queue *q)
330{
331 if (q->mq_ops)
332 blk_mq_start_hw_queues(q);
333 else
334 blk_run_queue(q);
335}
336
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337/*
338 * Called for single_lun devices on IO completion. Clear starget_sdev_user,
339 * and call blk_run_queue for all the scsi_devices on the target -
340 * including current_sdev first.
341 *
342 * Called with *no* scsi locks held.
343 */
344static void scsi_single_lun_run(struct scsi_device *current_sdev)
345{
346 struct Scsi_Host *shost = current_sdev->host;
347 struct scsi_device *sdev, *tmp;
348 struct scsi_target *starget = scsi_target(current_sdev);
349 unsigned long flags;
350
351 spin_lock_irqsave(shost->host_lock, flags);
352 starget->starget_sdev_user = NULL;
353 spin_unlock_irqrestore(shost->host_lock, flags);
354
355 /*
356 * Call blk_run_queue for all LUNs on the target, starting with
357 * current_sdev. We race with others (to set starget_sdev_user),
358 * but in most cases, we will be first. Ideally, each LU on the
359 * target would get some limited time or requests on the target.
360 */
Christoph Hellwigd2852032014-01-17 12:06:53 +0100361 scsi_kick_queue(current_sdev->request_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362
363 spin_lock_irqsave(shost->host_lock, flags);
364 if (starget->starget_sdev_user)
365 goto out;
366 list_for_each_entry_safe(sdev, tmp, &starget->devices,
367 same_target_siblings) {
368 if (sdev == current_sdev)
369 continue;
370 if (scsi_device_get(sdev))
371 continue;
372
373 spin_unlock_irqrestore(shost->host_lock, flags);
Christoph Hellwigd2852032014-01-17 12:06:53 +0100374 scsi_kick_queue(sdev->request_queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 spin_lock_irqsave(shost->host_lock, flags);
376
377 scsi_device_put(sdev);
378 }
379 out:
380 spin_unlock_irqrestore(shost->host_lock, flags);
381}
382
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100383static inline bool scsi_device_is_busy(struct scsi_device *sdev)
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400384{
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100385 if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
386 return true;
387 if (atomic_read(&sdev->device_blocked) > 0)
388 return true;
389 return false;
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400390}
391
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100392static inline bool scsi_target_is_busy(struct scsi_target *starget)
Mike Christief0c0a372008-08-17 15:24:38 -0500393{
Christoph Hellwig2ccbb002014-03-26 10:35:00 +0100394 if (starget->can_queue > 0) {
395 if (atomic_read(&starget->target_busy) >= starget->can_queue)
396 return true;
397 if (atomic_read(&starget->target_blocked) > 0)
398 return true;
399 }
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100400 return false;
Mike Christief0c0a372008-08-17 15:24:38 -0500401}
402
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100403static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400404{
Christoph Hellwigcd9070c2014-01-23 12:07:41 +0100405 if (shost->can_queue > 0 &&
406 atomic_read(&shost->host_busy) >= shost->can_queue)
407 return true;
408 if (atomic_read(&shost->host_blocked) > 0)
409 return true;
410 if (shost->host_self_blocked)
411 return true;
412 return false;
Kiyoshi Ueda9d112512008-10-04 14:11:06 -0400413}
414
Christoph Hellwig21a05df2014-02-20 14:20:54 -0800415static void scsi_starved_list_run(struct Scsi_Host *shost)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416{
Mike Christie2a3a59e2008-11-11 13:42:35 -0600417 LIST_HEAD(starved_list);
Christoph Hellwig21a05df2014-02-20 14:20:54 -0800418 struct scsi_device *sdev;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 unsigned long flags;
420
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 spin_lock_irqsave(shost->host_lock, flags);
Mike Christie2a3a59e2008-11-11 13:42:35 -0600422 list_splice_init(&shost->starved_list, &starved_list);
423
424 while (!list_empty(&starved_list)) {
James Bottomleye2eb7242013-07-02 15:05:26 +0200425 struct request_queue *slq;
426
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 /*
428 * As long as shost is accepting commands and we have
429 * starved queues, call blk_run_queue. scsi_request_fn
430 * drops the queue_lock and can add us back to the
431 * starved_list.
432 *
433 * host_lock protects the starved_list and starved_entry.
434 * scsi_request_fn must get the host_lock before checking
435 * or modifying starved_list or starved_entry.
436 */
Mike Christie2a3a59e2008-11-11 13:42:35 -0600437 if (scsi_host_is_busy(shost))
Mike Christief0c0a372008-08-17 15:24:38 -0500438 break;
Mike Christief0c0a372008-08-17 15:24:38 -0500439
Mike Christie2a3a59e2008-11-11 13:42:35 -0600440 sdev = list_entry(starved_list.next,
441 struct scsi_device, starved_entry);
442 list_del_init(&sdev->starved_entry);
Mike Christief0c0a372008-08-17 15:24:38 -0500443 if (scsi_target_is_busy(scsi_target(sdev))) {
444 list_move_tail(&sdev->starved_entry,
445 &shost->starved_list);
446 continue;
447 }
448
James Bottomleye2eb7242013-07-02 15:05:26 +0200449 /*
450 * Once we drop the host lock, a racing scsi_remove_device()
451 * call may remove the sdev from the starved list and destroy
452 * it and the queue. Mitigate by taking a reference to the
453 * queue and never touching the sdev again after we drop the
454 * host lock. Note: if __scsi_remove_device() invokes
455 * blk_cleanup_queue() before the queue is run from this
456 * function then blk_run_queue() will return immediately since
457 * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
458 */
459 slq = sdev->request_queue;
460 if (!blk_get_queue(slq))
461 continue;
462 spin_unlock_irqrestore(shost->host_lock, flags);
463
Christoph Hellwigd2852032014-01-17 12:06:53 +0100464 scsi_kick_queue(slq);
James Bottomleye2eb7242013-07-02 15:05:26 +0200465 blk_put_queue(slq);
466
467 spin_lock_irqsave(shost->host_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 }
Mike Christie2a3a59e2008-11-11 13:42:35 -0600469 /* put any unprocessed entries back */
470 list_splice(&starved_list, &shost->starved_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 spin_unlock_irqrestore(shost->host_lock, flags);
Christoph Hellwig21a05df2014-02-20 14:20:54 -0800472}
473
474/*
475 * Function: scsi_run_queue()
476 *
477 * Purpose: Select a proper request queue to serve next
478 *
479 * Arguments: q - last request's queue
480 *
481 * Returns: Nothing
482 *
483 * Notes: The previous command was completely finished, start
484 * a new one if possible.
485 */
486static void scsi_run_queue(struct request_queue *q)
487{
488 struct scsi_device *sdev = q->queuedata;
489
490 if (scsi_target(sdev)->single_lun)
491 scsi_single_lun_run(sdev);
492 if (!list_empty(&sdev->host->starved_list))
493 scsi_starved_list_run(sdev->host);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494
Christoph Hellwigd2852032014-01-17 12:06:53 +0100495 if (q->mq_ops)
496 blk_mq_start_stopped_hw_queues(q, false);
497 else
498 blk_run_queue(q);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499}
500
Jens Axboe9937a5e2011-05-17 11:04:44 +0200501void scsi_requeue_run_queue(struct work_struct *work)
502{
503 struct scsi_device *sdev;
504 struct request_queue *q;
505
506 sdev = container_of(work, struct scsi_device, requeue_work);
507 q = sdev->request_queue;
508 scsi_run_queue(q);
509}
510
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511/*
512 * Function: scsi_requeue_command()
513 *
514 * Purpose: Handle post-processing of completed commands.
515 *
516 * Arguments: q - queue to operate on
517 * cmd - command that may need to be requeued.
518 *
519 * Returns: Nothing
520 *
521 * Notes: After command completion, there may be blocks left
522 * over which weren't finished by the previous command
523 * this can be for a number of reasons - the main one is
524 * I/O errors in the middle of the request, in which case
525 * we need to request the blocks that come after the bad
526 * sector.
James Bottomleye91442b2005-09-09 10:44:16 -0500527 * Notes: Upon return, cmd is a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 */
529static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
530{
Bart Van Assche940f5d42012-06-29 15:34:26 +0000531 struct scsi_device *sdev = cmd->device;
James Bottomleye91442b2005-09-09 10:44:16 -0500532 struct request *req = cmd->request;
Tejun Heo 283369c2005-04-24 02:06:36 -0500533 unsigned long flags;
534
Tejun Heo 283369c2005-04-24 02:06:36 -0500535 spin_lock_irqsave(q->queue_lock, flags);
Christoph Hellwig134997a2014-02-20 14:20:58 -0800536 blk_unprep_request(req);
537 req->special = NULL;
538 scsi_put_command(cmd);
James Bottomleye91442b2005-09-09 10:44:16 -0500539 blk_requeue_request(q, req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500540 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541
542 scsi_run_queue(q);
Bart Van Assche940f5d42012-06-29 15:34:26 +0000543
544 put_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545}
546
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547void scsi_run_host_queues(struct Scsi_Host *shost)
548{
549 struct scsi_device *sdev;
550
551 shost_for_each_device(sdev, shost)
552 scsi_run_queue(sdev->request_queue);
553}
554
Jens Axboea8474ce2007-08-07 09:02:51 +0200555static inline unsigned int scsi_sgtable_index(unsigned short nents)
556{
557 unsigned int index;
558
James Bottomleyd3f46f32008-01-15 11:11:46 -0600559 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
560
561 if (nents <= 8)
Jens Axboea8474ce2007-08-07 09:02:51 +0200562 index = 0;
James Bottomleyd3f46f32008-01-15 11:11:46 -0600563 else
564 index = get_count_order(nents) - 3;
Jens Axboea8474ce2007-08-07 09:02:51 +0200565
566 return index;
567}
568
Jens Axboe5ed79592007-11-15 09:13:11 +0100569static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570{
571 struct scsi_host_sg_pool *sgp;
Jens Axboe5ed79592007-11-15 09:13:11 +0100572
573 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
574 mempool_free(sgl, sgp->pool);
575}
576
577static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
578{
579 struct scsi_host_sg_pool *sgp;
580
581 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
582 return mempool_alloc(sgp->pool, gfp_mask);
583}
584
Christoph Hellwigd2852032014-01-17 12:06:53 +0100585static void scsi_free_sgtable(struct scsi_data_buffer *sdb, bool mq)
Christoph Hellwigc53c6d62014-04-15 14:38:31 +0200586{
Tony Battersby0c958ec2015-07-16 11:40:41 -0400587 if (mq && sdb->table.orig_nents <= SCSI_MAX_SG_SEGMENTS)
Christoph Hellwigd2852032014-01-17 12:06:53 +0100588 return;
589 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, mq, scsi_sg_free);
Christoph Hellwigc53c6d62014-04-15 14:38:31 +0200590}
591
Christoph Hellwig3c356bd2014-09-05 18:20:23 -0700592static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, bool mq)
Jens Axboe5ed79592007-11-15 09:13:11 +0100593{
Christoph Hellwigd2852032014-01-17 12:06:53 +0100594 struct scatterlist *first_chunk = NULL;
Jens Axboe5ed79592007-11-15 09:13:11 +0100595 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200597 BUG_ON(!nents);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598
Christoph Hellwigd2852032014-01-17 12:06:53 +0100599 if (mq) {
600 if (nents <= SCSI_MAX_SG_SEGMENTS) {
Tony Battersby0c958ec2015-07-16 11:40:41 -0400601 sdb->table.nents = sdb->table.orig_nents = nents;
602 sg_init_table(sdb->table.sgl, nents);
Christoph Hellwigd2852032014-01-17 12:06:53 +0100603 return 0;
604 }
605 first_chunk = sdb->table.sgl;
606 }
607
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200608 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
Christoph Hellwig70a0f2c2015-01-05 20:29:38 +0100609 first_chunk, GFP_ATOMIC, scsi_sg_alloc);
Jens Axboe5ed79592007-11-15 09:13:11 +0100610 if (unlikely(ret))
Christoph Hellwigd2852032014-01-17 12:06:53 +0100611 scsi_free_sgtable(sdb, mq);
Jens Axboea8474ce2007-08-07 09:02:51 +0200612 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613}
614
Christoph Hellwigd2852032014-01-17 12:06:53 +0100615static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
616{
617 if (cmd->request->cmd_type == REQ_TYPE_FS) {
618 struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
619
620 if (drv->uninit_command)
621 drv->uninit_command(cmd);
622 }
623}
624
625static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
626{
627 if (cmd->sdb.table.nents)
628 scsi_free_sgtable(&cmd->sdb, true);
629 if (cmd->request->next_rq && cmd->request->next_rq->special)
630 scsi_free_sgtable(cmd->request->next_rq->special, true);
631 if (scsi_prot_sg_count(cmd))
632 scsi_free_sgtable(cmd->prot_sdb, true);
633}
634
635static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
636{
637 struct scsi_device *sdev = cmd->device;
Kashyap.Desai@avagotech.com64bdcbc2014-08-20 19:24:33 +0530638 struct Scsi_Host *shost = sdev->host;
Christoph Hellwigd2852032014-01-17 12:06:53 +0100639 unsigned long flags;
640
Christoph Hellwigd2852032014-01-17 12:06:53 +0100641 scsi_mq_free_sgtables(cmd);
642 scsi_uninit_cmd(cmd);
643
Kashyap.Desai@avagotech.com64bdcbc2014-08-20 19:24:33 +0530644 if (shost->use_cmd_list) {
645 BUG_ON(list_empty(&cmd->list));
646 spin_lock_irqsave(&sdev->list_lock, flags);
647 list_del_init(&cmd->list);
648 spin_unlock_irqrestore(&sdev->list_lock, flags);
649 }
Christoph Hellwigd2852032014-01-17 12:06:53 +0100650}
651
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652/*
653 * Function: scsi_release_buffers()
654 *
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200655 * Purpose: Free resources allocate for a scsi_command.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 *
657 * Arguments: cmd - command that we are bailing.
658 *
659 * Lock status: Assumed that no lock is held upon entry.
660 *
661 * Returns: Nothing
662 *
663 * Notes: In the event that an upper level driver rejects a
664 * command, we must release resources allocated during
665 * the __init_io() function. Primarily this would involve
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200666 * the scatter-gather table.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 */
Christoph Hellwigf1bea552014-04-15 12:26:54 +0200668static void scsi_release_buffers(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669{
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200670 if (cmd->sdb.table.nents)
Christoph Hellwigd2852032014-01-17 12:06:53 +0100671 scsi_free_sgtable(&cmd->sdb, false);
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200672
673 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
674
675 if (scsi_prot_sg_count(cmd))
Christoph Hellwigd2852032014-01-17 12:06:53 +0100676 scsi_free_sgtable(cmd->prot_sdb, false);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677}
678
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200679static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
680{
681 struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
682
Christoph Hellwigd2852032014-01-17 12:06:53 +0100683 scsi_free_sgtable(bidi_sdb, false);
Christoph Hellwigc682adf2014-05-01 16:51:02 +0200684 kmem_cache_free(scsi_sdb_cache, bidi_sdb);
685 cmd->request->next_rq->special = NULL;
686}
687
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800688static bool scsi_end_request(struct request *req, int error,
689 unsigned int bytes, unsigned int bidi_bytes)
690{
691 struct scsi_cmnd *cmd = req->special;
692 struct scsi_device *sdev = cmd->device;
693 struct request_queue *q = sdev->request_queue;
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800694
695 if (blk_update_request(req, error, bytes))
696 return true;
697
698 /* Bidi request must be completed as a whole */
699 if (unlikely(bidi_bytes) &&
700 blk_update_request(req->next_rq, error, bidi_bytes))
701 return true;
702
703 if (blk_queue_add_random(q))
704 add_disk_randomness(req->rq_disk);
705
Christoph Hellwigd2852032014-01-17 12:06:53 +0100706 if (req->mq_ctx) {
707 /*
Christoph Hellwigc8a446a2014-09-13 16:40:10 -0700708 * In the MQ case the command gets freed by __blk_mq_end_request,
Christoph Hellwigd2852032014-01-17 12:06:53 +0100709 * so we have to do all cleanup that depends on it earlier.
710 *
711 * We also can't kick the queues from irq context, so we
712 * will have to defer it to a workqueue.
713 */
714 scsi_mq_uninit_cmd(cmd);
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800715
Christoph Hellwigc8a446a2014-09-13 16:40:10 -0700716 __blk_mq_end_request(req, error);
Christoph Hellwigd2852032014-01-17 12:06:53 +0100717
718 if (scsi_target(sdev)->single_lun ||
719 !list_empty(&sdev->host->starved_list))
720 kblockd_schedule_work(&sdev->requeue_work);
721 else
722 blk_mq_start_stopped_hw_queues(q, true);
Christoph Hellwigd2852032014-01-17 12:06:53 +0100723 } else {
724 unsigned long flags;
725
Daniel Gryniewiczf81426a2014-09-16 10:41:13 -0400726 if (bidi_bytes)
727 scsi_release_bidi_buffers(cmd);
728
Christoph Hellwigd2852032014-01-17 12:06:53 +0100729 spin_lock_irqsave(q->queue_lock, flags);
730 blk_finish_request(req, error);
731 spin_unlock_irqrestore(q->queue_lock, flags);
732
Christoph Hellwigd2852032014-01-17 12:06:53 +0100733 scsi_release_buffers(cmd);
Christoph Hellwigbb3ec622014-09-05 18:02:09 -0700734
735 scsi_put_command(cmd);
736 scsi_run_queue(q);
Christoph Hellwigd2852032014-01-17 12:06:53 +0100737 }
738
Christoph Hellwigbb3ec622014-09-05 18:02:09 -0700739 put_device(&sdev->sdev_gendev);
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800740 return false;
741}
742
Hannes Reinecke0f7f6232013-07-01 15:16:23 +0200743/**
744 * __scsi_error_from_host_byte - translate SCSI error code into errno
745 * @cmd: SCSI command (unused)
746 * @result: scsi error code
747 *
748 * Translate SCSI error code into standard UNIX errno.
749 * Return values:
750 * -ENOLINK temporary transport failure
751 * -EREMOTEIO permanent target failure, do not retry
752 * -EBADE permanent nexus failure, retry on other path
Hannes Reineckea9d6ceb82013-07-01 15:16:25 +0200753 * -ENOSPC No write space available
Hannes Reinecke7e782af2013-07-01 15:16:26 +0200754 * -ENODATA Medium error
Hannes Reinecke0f7f6232013-07-01 15:16:23 +0200755 * -EIO unspecified I/O error
756 */
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100757static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result)
758{
759 int error = 0;
760
761 switch(host_byte(result)) {
762 case DID_TRANSPORT_FAILFAST:
763 error = -ENOLINK;
764 break;
765 case DID_TARGET_FAILURE:
Moger, Babu2082ebc2012-01-24 20:38:46 +0000766 set_host_byte(cmd, DID_OK);
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100767 error = -EREMOTEIO;
768 break;
769 case DID_NEXUS_FAILURE:
Moger, Babu2082ebc2012-01-24 20:38:46 +0000770 set_host_byte(cmd, DID_OK);
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100771 error = -EBADE;
772 break;
Hannes Reineckea9d6ceb82013-07-01 15:16:25 +0200773 case DID_ALLOC_FAILURE:
774 set_host_byte(cmd, DID_OK);
775 error = -ENOSPC;
776 break;
Hannes Reinecke7e782af2013-07-01 15:16:26 +0200777 case DID_MEDIUM_ERROR:
778 set_host_byte(cmd, DID_OK);
779 error = -ENODATA;
780 break;
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100781 default:
782 error = -EIO;
783 break;
784 }
785
786 return error;
787}
788
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789/*
790 * Function: scsi_io_completion()
791 *
792 * Purpose: Completion processing for block device I/O requests.
793 *
794 * Arguments: cmd - command that is finished.
795 *
796 * Lock status: Assumed that no lock is held upon entry.
797 *
798 * Returns: Nothing
799 *
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200800 * Notes: We will finish off the specified number of sectors. If we
801 * are done, the command block will be released and the queue
802 * function will be goosed. If we are not done then we have to
Alan Sternb60af5b2008-11-03 15:56:47 -0500803 * figure out what to do next:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 *
Alan Sternb60af5b2008-11-03 15:56:47 -0500805 * a) We can call scsi_requeue_command(). The request
806 * will be unprepared and put back on the queue. Then
807 * a new command will be created for it. This should
808 * be used if we made forward progress, or if we want
809 * to switch from READ(10) to READ(6) for example.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 *
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200811 * b) We can call __scsi_queue_insert(). The request will
Alan Sternb60af5b2008-11-03 15:56:47 -0500812 * be put back on the queue and retried using the same
813 * command as before, possibly after a delay.
814 *
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800815 * c) We can call scsi_end_request() with -EIO to fail
Alan Sternb60af5b2008-11-03 15:56:47 -0500816 * the remainder of the request.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817 */
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700818void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819{
820 int result = cmd->result;
Jens Axboe165125e2007-07-24 09:28:11 +0200821 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 struct request *req = cmd->request;
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500823 int error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 struct scsi_sense_hdr sshdr;
Hannes Reinecke4753cbc2014-10-24 14:26:52 +0200825 bool sense_valid = false;
Hannes Reineckec11c0042014-10-24 14:27:01 +0200826 int sense_deferred = 0, level = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500827 enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
828 ACTION_DELAYED_RETRY} action;
Eiichi Tsukataee60b2c2014-02-11 14:29:52 +0900829 unsigned long wait_for = (cmd->allowed + 1) * req->timeout;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 if (result) {
832 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
833 if (sense_valid)
834 sense_deferred = scsi_sense_is_deferred(&sshdr);
835 }
Christoph Hellwig631c2282006-07-08 20:42:15 +0200836
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200837 if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 if (result) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 if (sense_valid && req->sense) {
840 /*
841 * SG_IO wants current and deferred errors
842 */
843 int len = 8 + cmd->sense_buffer[7];
844
845 if (len > SCSI_SENSE_BUFFERSIZE)
846 len = SCSI_SENSE_BUFFERSIZE;
847 memcpy(req->sense, cmd->sense_buffer, len);
848 req->sense_len = len;
849 }
James Bottomleyfa8e36c2008-04-02 18:11:52 -0500850 if (!sense_deferred)
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100851 error = __scsi_error_from_host_byte(cmd, result);
Pete Wyckoffb22f6872007-03-13 16:53:28 -0400852 }
Mike Snitzer27c41972012-05-31 15:05:33 -0400853 /*
854 * __scsi_error_from_host_byte may have reset the host_byte
855 */
856 req->errors = cmd->result;
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900857
858 req->resid_len = scsi_get_resid(cmd);
859
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200860 if (scsi_bidi_cmnd(cmd)) {
FUJITA Tomonorie6bb7a962009-05-11 17:56:08 +0900861 /*
862 * Bidi commands Must be complete as a whole,
863 * both sides at once.
864 */
865 req->next_rq->resid_len = scsi_in(cmd)->resid;
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800866 if (scsi_end_request(req, 0, blk_rq_bytes(req),
867 blk_rq_bytes(req->next_rq)))
868 BUG();
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200869 return;
870 }
James Bottomley89fb4cd2014-07-03 19:17:34 +0200871 } else if (blk_rq_bytes(req) == 0 && result && !sense_deferred) {
872 /*
873 * Certain non BLOCK_PC requests are commands that don't
874 * actually transfer anything (FLUSH), so cannot use
875 * good_bytes != blk_rq_bytes(req) as the signal for an error.
876 * This sets the error explicitly for the problem case.
877 */
878 error = __scsi_error_from_host_byte(cmd, result);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 }
880
Christoph Hellwig33659eb2010-08-07 18:17:56 +0200881 /* no bidi support for !REQ_TYPE_BLOCK_PC yet */
882 BUG_ON(blk_bidi_rq(req));
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200883
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 * Next deal with any sectors which we were able to correctly
886 * handle.
887 */
Hannes Reinecke91921e02014-06-25 16:39:59 +0200888 SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
889 "%u sectors total, %d bytes done.\n",
890 blk_rq_sectors(req), good_bytes));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891
James Bottomleya9bddd72009-03-30 16:55:51 +0000892 /*
893 * Recovered errors need reporting, but they're always treated
894 * as success, so fiddle the result code here. For BLOCK_PC
895 * we already took a copy of the original into rq->errors which
896 * is what gets returned to the user
897 */
Douglas Gilberte7efe592010-01-03 13:51:15 -0500898 if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
899 /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip
900 * print since caller wants ATA registers. Only occurs on
901 * SCSI ATA PASS_THROUGH commands when CK_COND=1
902 */
903 if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
904 ;
905 else if (!(req->cmd_flags & REQ_QUIET))
Hannes Reinecked811b842014-10-24 14:26:45 +0200906 scsi_print_sense(cmd);
James Bottomleya9bddd72009-03-30 16:55:51 +0000907 result = 0;
908 /* BLOCK_PC may have set error */
909 error = 0;
910 }
911
912 /*
James Bottomley0dec8c02016-05-13 12:04:06 -0700913 * special case: failed zero length commands always need to
914 * drop down into the retry code. Otherwise, if we finished
915 * all bytes in the request we are done now.
James Bottomleyd6b0c532006-07-02 10:06:28 -0500916 */
James Bottomley0dec8c02016-05-13 12:04:06 -0700917 if (!(blk_rq_bytes(req) == 0 && error) &&
918 !scsi_end_request(req, error, good_bytes, 0))
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800919 return;
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200920
921 /*
922 * Kill remainder if no retrys.
923 */
924 if (error && scsi_noretry_cmd(cmd)) {
Christoph Hellwigf6d47e72014-02-16 06:16:13 -0800925 if (scsi_end_request(req, error, blk_rq_bytes(req), 0))
926 BUG();
927 return;
Christoph Hellwigbc85dc52014-05-01 16:51:03 +0200928 }
929
930 /*
931 * If there had been no error, but we have leftover bytes in the
932 * requeues just queue the command up again.
933 */
934 if (result == 0)
935 goto requeue;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700936
Hannes Reinecke63583cc2011-01-18 10:13:11 +0100937 error = __scsi_error_from_host_byte(cmd, result);
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500938
Alan Sternb60af5b2008-11-03 15:56:47 -0500939 if (host_byte(result) == DID_RESET) {
940 /* Third party bus reset or reset for error recovery
941 * reasons. Just retry the command and see what
942 * happens.
943 */
944 action = ACTION_RETRY;
945 } else if (sense_valid && !sense_deferred) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946 switch (sshdr.sense_key) {
947 case UNIT_ATTENTION:
948 if (cmd->device->removable) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700949 /* Detected disc change. Set a bit
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950 * and quietly refuse further access.
951 */
952 cmd->device->changed = 1;
Alan Sternb60af5b2008-11-03 15:56:47 -0500953 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 } else {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700955 /* Must have been a power glitch, or a
956 * bus reset. Could not have been a
957 * media change, so we just retry the
Alan Sternb60af5b2008-11-03 15:56:47 -0500958 * command and see what happens.
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700959 */
Alan Sternb60af5b2008-11-03 15:56:47 -0500960 action = ACTION_RETRY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 }
962 break;
963 case ILLEGAL_REQUEST:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700964 /* If we had an ILLEGAL REQUEST returned, then
965 * we may have performed an unsupported
966 * command. The only thing this should be
967 * would be a ten byte read where only a six
968 * byte read was supported. Also, on a system
969 * where READ CAPACITY failed, we may have
970 * read past the end of the disk.
971 */
Jens Axboe26a68012005-11-29 21:03:34 +0100972 if ((cmd->device->use_10_for_rw &&
973 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974 (cmd->cmnd[0] == READ_10 ||
975 cmd->cmnd[0] == WRITE_10)) {
Alan Sternb60af5b2008-11-03 15:56:47 -0500976 /* This will issue a new 6-byte command. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 cmd->device->use_10_for_rw = 0;
Alan Sternb60af5b2008-11-03 15:56:47 -0500978 action = ACTION_REPREP;
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500979 } else if (sshdr.asc == 0x10) /* DIX */ {
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500980 action = ACTION_FAIL;
981 error = -EILSEQ;
Martin K. Petersenc98a0eb2011-03-08 02:07:15 -0500982 /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
Martin K. Petersen5db44862012-09-18 12:19:32 -0400983 } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
Martin K. Petersenc98a0eb2011-03-08 02:07:15 -0500984 action = ACTION_FAIL;
Martin K. Petersen66a651a2012-02-13 15:38:22 -0500985 error = -EREMOTEIO;
Alan Sternb60af5b2008-11-03 15:56:47 -0500986 } else
987 action = ACTION_FAIL;
988 break;
Martin K. Petersen511e44f2008-07-17 04:28:33 -0400989 case ABORTED_COMMAND:
James Bottomley126c09822009-02-19 21:48:54 +0000990 action = ACTION_FAIL;
Maurizio Lombardie6c11db2014-07-10 09:41:53 +0200991 if (sshdr.asc == 0x10) /* DIF */
Martin K. Petersen3e695f82009-01-04 03:04:31 -0500992 error = -EILSEQ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993 break;
994 case NOT_READY:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700995 /* If the device is in the process of becoming
James Bottomleyf3e93f72006-04-25 16:48:30 -0500996 * ready, or has a temporary blockage, retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 */
James Bottomleyf3e93f72006-04-25 16:48:30 -0500998 if (sshdr.asc == 0x04) {
999 switch (sshdr.ascq) {
1000 case 0x01: /* becoming ready */
1001 case 0x04: /* format in progress */
1002 case 0x05: /* rebuild in progress */
1003 case 0x06: /* recalculation in progress */
1004 case 0x07: /* operation in progress */
1005 case 0x08: /* Long write in progress */
1006 case 0x09: /* self test in progress */
Martin K. Petersend8705f12009-11-26 12:00:41 -05001007 case 0x14: /* space allocation in progress */
Alan Sternb60af5b2008-11-03 15:56:47 -05001008 action = ACTION_DELAYED_RETRY;
James Bottomleyf3e93f72006-04-25 16:48:30 -05001009 break;
Alan Stern3dbf6a52008-12-15 10:31:28 -05001010 default:
Alan Stern3dbf6a52008-12-15 10:31:28 -05001011 action = ACTION_FAIL;
1012 break;
James Bottomleyf3e93f72006-04-25 16:48:30 -05001013 }
Maurizio Lombardie6c11db2014-07-10 09:41:53 +02001014 } else
Alan Sternb60af5b2008-11-03 15:56:47 -05001015 action = ACTION_FAIL;
Alan Sternb60af5b2008-11-03 15:56:47 -05001016 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017 case VOLUME_OVERFLOW:
Luben Tuikov03aba2f2006-06-23 09:39:09 -07001018 /* See SSC3rXX or current. */
Alan Sternb60af5b2008-11-03 15:56:47 -05001019 action = ACTION_FAIL;
1020 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 default:
Alan Sternb60af5b2008-11-03 15:56:47 -05001022 action = ACTION_FAIL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023 break;
1024 }
Maurizio Lombardie6c11db2014-07-10 09:41:53 +02001025 } else
Alan Sternb60af5b2008-11-03 15:56:47 -05001026 action = ACTION_FAIL;
Alan Sternb60af5b2008-11-03 15:56:47 -05001027
Eiichi Tsukataee60b2c2014-02-11 14:29:52 +09001028 if (action != ACTION_FAIL &&
Maurizio Lombardie6c11db2014-07-10 09:41:53 +02001029 time_before(cmd->jiffies_at_alloc + wait_for, jiffies))
Eiichi Tsukataee60b2c2014-02-11 14:29:52 +09001030 action = ACTION_FAIL;
Eiichi Tsukataee60b2c2014-02-11 14:29:52 +09001031
Alan Sternb60af5b2008-11-03 15:56:47 -05001032 switch (action) {
1033 case ACTION_FAIL:
1034 /* Give up and fail the remainder of the request */
Hannes Reineckef1569ff2014-10-24 14:27:07 +02001035 if (!(req->cmd_flags & REQ_QUIET)) {
1036 static DEFINE_RATELIMIT_STATE(_rs,
1037 DEFAULT_RATELIMIT_INTERVAL,
1038 DEFAULT_RATELIMIT_BURST);
1039
1040 if (unlikely(scsi_logging_level))
1041 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
1042 SCSI_LOG_MLCOMPLETE_BITS);
1043
1044 /*
1045 * if logging is enabled the failure will be printed
1046 * in scsi_log_completion(), so avoid duplicate messages
1047 */
1048 if (!level && __ratelimit(&_rs)) {
1049 scsi_print_result(cmd, NULL, FAILED);
1050 if (driver_byte(result) & DRIVER_SENSE)
1051 scsi_print_sense(cmd);
1052 scsi_print_command(cmd);
1053 }
James Bottomley3173d8c2005-09-04 11:32:05 -05001054 }
Christoph Hellwigf6d47e72014-02-16 06:16:13 -08001055 if (!scsi_end_request(req, error, blk_rq_err_bytes(req), 0))
1056 return;
Christoph Hellwigbc85dc52014-05-01 16:51:03 +02001057 /*FALLTHRU*/
Alan Sternb60af5b2008-11-03 15:56:47 -05001058 case ACTION_REPREP:
Christoph Hellwigbc85dc52014-05-01 16:51:03 +02001059 requeue:
Alan Sternb60af5b2008-11-03 15:56:47 -05001060 /* Unprep the request and put it back at the head of the queue.
1061 * A new command will be prepared and issued.
1062 */
Christoph Hellwigd2852032014-01-17 12:06:53 +01001063 if (q->mq_ops) {
1064 cmd->request->cmd_flags &= ~REQ_DONTPREP;
1065 scsi_mq_uninit_cmd(cmd);
1066 scsi_mq_requeue_cmd(cmd);
1067 } else {
1068 scsi_release_buffers(cmd);
1069 scsi_requeue_command(q, cmd);
1070 }
Alan Sternb60af5b2008-11-03 15:56:47 -05001071 break;
1072 case ACTION_RETRY:
1073 /* Retry the same command immediately */
James Bottomley4f5299a2009-01-02 10:42:21 -06001074 __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -05001075 break;
1076 case ACTION_DELAYED_RETRY:
1077 /* Retry the same command after a delay */
James Bottomley4f5299a2009-01-02 10:42:21 -06001078 __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0);
Alan Sternb60af5b2008-11-03 15:56:47 -05001079 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 }
1081}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001083static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084{
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001085 int count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086
1087 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001088 * If sg table allocation fails, requeue request later.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001090 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001091 req->mq_ctx != NULL)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 return BLKPREP_DEFER;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 /*
1095 * Next, walk the list, and fill in the addresses and sizes of
1096 * each segment.
1097 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001098 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1099 BUG_ON(count > sdb->table.nents);
1100 sdb->table.nents = count;
Tejun Heo1011c1b2009-05-07 22:24:45 +09001101 sdb->length = blk_rq_bytes(req);
Rusty Russell4a03d902007-11-19 11:28:48 +11001102 return BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103}
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001104
1105/*
1106 * Function: scsi_init_io()
1107 *
1108 * Purpose: SCSI I/O initialize function.
1109 *
1110 * Arguments: cmd - Command descriptor we wish to initialize
1111 *
1112 * Returns: 0 on success
1113 * BLKPREP_DEFER if the failure is retryable
1114 * BLKPREP_KILL if the failure is fatal
1115 */
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001116int scsi_init_io(struct scsi_cmnd *cmd)
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001117{
Christoph Hellwig5e012aa2014-04-15 12:24:55 +02001118 struct scsi_device *sdev = cmd->device;
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001119 struct request *rq = cmd->request;
Christoph Hellwigd2852032014-01-17 12:06:53 +01001120 bool is_mq = (rq->mq_ctx != NULL);
Christoph Hellwig635d98b2014-06-28 11:51:01 +02001121 int error;
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001122
Christoph Hellwig635d98b2014-06-28 11:51:01 +02001123 BUG_ON(!rq->nr_phys_segments);
1124
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001125 error = scsi_init_sgtable(rq, &cmd->sdb);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001126 if (error)
1127 goto err_exit;
1128
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001129 if (blk_bidi_rq(rq)) {
Christoph Hellwigd2852032014-01-17 12:06:53 +01001130 if (!rq->q->mq_ops) {
1131 struct scsi_data_buffer *bidi_sdb =
1132 kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC);
1133 if (!bidi_sdb) {
1134 error = BLKPREP_DEFER;
1135 goto err_exit;
1136 }
1137
1138 rq->next_rq->special = bidi_sdb;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001139 }
1140
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001141 error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special);
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001142 if (error)
1143 goto err_exit;
1144 }
1145
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001146 if (blk_integrity_rq(rq)) {
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001147 struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1148 int ivecs, count;
1149
Ewan D. Milne91724c22015-01-15 10:02:12 -05001150 if (prot_sdb == NULL) {
1151 /*
1152 * This can happen if someone (e.g. multipath)
1153 * queues a command to a device on an adapter
1154 * that does not support DIX.
1155 */
1156 WARN_ON_ONCE(1);
1157 error = BLKPREP_KILL;
1158 goto err_exit;
1159 }
1160
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001161 ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001162
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001163 if (scsi_alloc_sgtable(prot_sdb, ivecs, is_mq)) {
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001164 error = BLKPREP_DEFER;
1165 goto err_exit;
1166 }
1167
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001168 count = blk_rq_map_integrity_sg(rq->q, rq->bio,
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001169 prot_sdb->table.sgl);
1170 BUG_ON(unlikely(count > ivecs));
Martin K. Petersen13f05c82010-09-10 20:50:10 +02001171 BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q)));
Martin K. Petersen7027ad72008-07-17 17:08:48 -04001172
1173 cmd->prot_sdb = prot_sdb;
1174 cmd->prot_sdb->table.nents = count;
1175 }
1176
Christoph Hellwigd2852032014-01-17 12:06:53 +01001177 return BLKPREP_OK;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001178err_exit:
Christoph Hellwigd2852032014-01-17 12:06:53 +01001179 if (is_mq) {
1180 scsi_mq_free_sgtables(cmd);
1181 } else {
1182 scsi_release_buffers(cmd);
1183 cmd->request->special = NULL;
1184 scsi_put_command(cmd);
1185 put_device(&sdev->sdev_gendev);
1186 }
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001187 return error;
1188}
Boaz Harroshbb52d822007-12-13 16:14:27 -08001189EXPORT_SYMBOL(scsi_init_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190
Christoph Hellwig3b003152006-11-04 20:10:55 +01001191static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
1192 struct request *req)
1193{
1194 struct scsi_cmnd *cmd;
1195
1196 if (!req->special) {
Christoph Hellwig04796332014-02-20 14:20:55 -08001197 /* Bail if we can't get a reference to the device */
1198 if (!get_device(&sdev->sdev_gendev))
Christoph Hellwig3b003152006-11-04 20:10:55 +01001199 return NULL;
Christoph Hellwig04796332014-02-20 14:20:55 -08001200
1201 cmd = scsi_get_command(sdev, GFP_ATOMIC);
1202 if (unlikely(!cmd)) {
1203 put_device(&sdev->sdev_gendev);
1204 return NULL;
1205 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001206 req->special = cmd;
1207 } else {
1208 cmd = req->special;
1209 }
1210
1211 /* pull a tag out of the request if we have one */
1212 cmd->tag = req->tag;
1213 cmd->request = req;
1214
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001215 cmd->cmnd = req->cmd;
Martin K. Petersen72f7d322011-03-08 02:03:59 -05001216 cmd->prot_op = SCSI_PROT_NORMAL;
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001217
Christoph Hellwig3b003152006-11-04 20:10:55 +01001218 return cmd;
1219}
1220
Christoph Hellwig4f1e5762014-06-28 12:36:28 +02001221static int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
James Bottomley7b163182005-12-15 20:17:02 -06001222{
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001223 struct scsi_cmnd *cmd = req->special;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001224
1225 /*
1226 * BLOCK_PC requests may transfer data, in which case they must
1227 * a bio attached to them. Or they might contain a SCSI command
1228 * that does not transfer data, in which case they may optionally
1229 * submit a request without an attached bio.
1230 */
1231 if (req->bio) {
Christoph Hellwig3c356bd2014-09-05 18:20:23 -07001232 int ret = scsi_init_io(cmd);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001233 if (unlikely(ret))
1234 return ret;
1235 } else {
Tejun Heob0790412009-05-07 22:24:42 +09001236 BUG_ON(blk_rq_bytes(req));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001237
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001238 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001239 }
James Bottomley7b163182005-12-15 20:17:02 -06001240
James Bottomley7b163182005-12-15 20:17:02 -06001241 cmd->cmd_len = req->cmd_len;
Tejun Heob0790412009-05-07 22:24:42 +09001242 cmd->transfersize = blk_rq_bytes(req);
James Bottomley7b163182005-12-15 20:17:02 -06001243 cmd->allowed = req->retries;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001244 return BLKPREP_OK;
1245}
1246
1247/*
Christoph Hellwig3868cf82014-06-28 11:58:42 +02001248 * Setup a REQ_TYPE_FS command. These are simple request from filesystems
1249 * that still need to be translated to SCSI CDBs from the ULD.
Christoph Hellwig3b003152006-11-04 20:10:55 +01001250 */
Christoph Hellwig3868cf82014-06-28 11:58:42 +02001251static int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
Christoph Hellwig3b003152006-11-04 20:10:55 +01001252{
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001253 struct scsi_cmnd *cmd = req->special;
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001254
Christoph Hellwigee14c672015-08-27 14:16:59 +02001255 if (unlikely(sdev->handler && sdev->handler->prep_fn)) {
1256 int ret = sdev->handler->prep_fn(sdev, req);
Chandra Seetharamana6a8d9f2008-05-01 14:49:46 -07001257 if (ret != BLKPREP_OK)
1258 return ret;
1259 }
1260
Boaz Harrosh64a87b22008-04-30 11:19:47 +03001261 memset(cmd->cmnd, 0, BLK_MAX_CDB);
Christoph Hellwig3868cf82014-06-28 11:58:42 +02001262 return scsi_cmd_to_driver(cmd)->init_command(cmd);
James Bottomley7b163182005-12-15 20:17:02 -06001263}
James Bottomley7b163182005-12-15 20:17:02 -06001264
Christoph Hellwig6af7a4f2014-07-08 13:16:17 +02001265static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
1266{
1267 struct scsi_cmnd *cmd = req->special;
1268
1269 if (!blk_rq_bytes(req))
1270 cmd->sc_data_direction = DMA_NONE;
1271 else if (rq_data_dir(req) == WRITE)
1272 cmd->sc_data_direction = DMA_TO_DEVICE;
1273 else
1274 cmd->sc_data_direction = DMA_FROM_DEVICE;
1275
1276 switch (req->cmd_type) {
1277 case REQ_TYPE_FS:
1278 return scsi_setup_fs_cmnd(sdev, req);
1279 case REQ_TYPE_BLOCK_PC:
1280 return scsi_setup_blk_pc_cmnd(sdev, req);
1281 default:
1282 return BLKPREP_KILL;
1283 }
1284}
1285
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001286static int
1287scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001289 int ret = BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001290
1291 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001292 * If the device is not in running state we will reject some
1293 * or all commands.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001295 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
Christoph Hellwig3b003152006-11-04 20:10:55 +01001296 switch (sdev->sdev_state) {
1297 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05001298 case SDEV_TRANSPORT_OFFLINE:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001299 /*
1300 * If the device is offline we refuse to process any
1301 * commands. The device must be brought online
1302 * before trying any recovery commands.
1303 */
1304 sdev_printk(KERN_ERR, sdev,
1305 "rejecting I/O to offline device\n");
1306 ret = BLKPREP_KILL;
1307 break;
1308 case SDEV_DEL:
1309 /*
1310 * If the device is fully deleted, we refuse to
1311 * process any commands as well.
1312 */
James Bottomley9ccfc752005-10-02 11:45:08 -05001313 sdev_printk(KERN_ERR, sdev,
1314 "rejecting I/O to dead device\n");
Christoph Hellwig3b003152006-11-04 20:10:55 +01001315 ret = BLKPREP_KILL;
1316 break;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001317 case SDEV_BLOCK:
James Bottomley6f4267e2008-08-22 16:53:31 -05001318 case SDEV_CREATED_BLOCK:
Bart Van Asschebba0bdd2015-03-04 10:31:47 +01001319 ret = BLKPREP_DEFER;
1320 break;
1321 case SDEV_QUIESCE:
Christoph Hellwig3b003152006-11-04 20:10:55 +01001322 /*
1323 * If the devices is blocked we defer normal commands.
1324 */
1325 if (!(req->cmd_flags & REQ_PREEMPT))
1326 ret = BLKPREP_DEFER;
1327 break;
1328 default:
1329 /*
1330 * For any other not fully online state we only allow
1331 * special commands. In particular any user initiated
1332 * command is not allowed.
1333 */
1334 if (!(req->cmd_flags & REQ_PREEMPT))
1335 ret = BLKPREP_KILL;
1336 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001337 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338 }
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001339 return ret;
1340}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001341
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001342static int
1343scsi_prep_return(struct request_queue *q, struct request *req, int ret)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001344{
1345 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346
Christoph Hellwig3b003152006-11-04 20:10:55 +01001347 switch (ret) {
1348 case BLKPREP_KILL:
1349 req->errors = DID_NO_CONNECT << 16;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001350 /* release the command and kill it */
1351 if (req->special) {
1352 struct scsi_cmnd *cmd = req->special;
1353 scsi_release_buffers(cmd);
1354 scsi_put_command(cmd);
Christoph Hellwig68c03d92014-04-15 12:24:56 +02001355 put_device(&sdev->sdev_gendev);
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001356 req->special = NULL;
1357 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001358 break;
1359 case BLKPREP_DEFER:
1360 /*
Tejun Heo9934c8c2009-05-08 11:54:16 +09001361 * If we defer, the blk_peek_request() returns NULL, but the
Jens Axboea488e742010-04-16 21:13:15 +02001362 * queue must be restarted, so we schedule a callback to happen
1363 * shortly.
Christoph Hellwig3b003152006-11-04 20:10:55 +01001364 */
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001365 if (atomic_read(&sdev->device_busy) == 0)
Jens Axboea488e742010-04-16 21:13:15 +02001366 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001367 break;
1368 default:
1369 req->cmd_flags |= REQ_DONTPREP;
1370 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001371
Christoph Hellwig3b003152006-11-04 20:10:55 +01001372 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001373}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001374
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001375static int scsi_prep_fn(struct request_queue *q, struct request *req)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001376{
1377 struct scsi_device *sdev = q->queuedata;
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001378 struct scsi_cmnd *cmd;
1379 int ret;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001380
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001381 ret = scsi_prep_state_check(sdev, req);
1382 if (ret != BLKPREP_OK)
1383 goto out;
1384
1385 cmd = scsi_get_cmd_from_req(sdev, req);
1386 if (unlikely(!cmd)) {
1387 ret = BLKPREP_DEFER;
1388 goto out;
1389 }
1390
Christoph Hellwig6af7a4f2014-07-08 13:16:17 +02001391 ret = scsi_setup_cmnd(sdev, req);
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001392out:
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001393 return scsi_prep_return(q, req, ret);
1394}
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001395
1396static void scsi_unprep_fn(struct request_queue *q, struct request *req)
1397{
Christoph Hellwigd2852032014-01-17 12:06:53 +01001398 scsi_uninit_cmd(req->special);
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02001399}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001400
1401/*
1402 * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1403 * return 0.
1404 *
1405 * Called with the queue_lock held.
1406 */
1407static inline int scsi_dev_queue_ready(struct request_queue *q,
1408 struct scsi_device *sdev)
1409{
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001410 unsigned int busy;
1411
1412 busy = atomic_inc_return(&sdev->device_busy) - 1;
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001413 if (atomic_read(&sdev->device_blocked)) {
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001414 if (busy)
1415 goto out_dec;
1416
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417 /*
1418 * unblock after device_blocked iterates to zero
1419 */
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001420 if (atomic_dec_return(&sdev->device_blocked) > 0) {
Christoph Hellwigd2852032014-01-17 12:06:53 +01001421 /*
1422 * For the MQ case we take care of this in the caller.
1423 */
1424 if (!q->mq_ops)
1425 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001426 goto out_dec;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427 }
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001428 SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1429 "unblocking device at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430 }
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001431
1432 if (busy >= sdev->queue_depth)
1433 goto out_dec;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001434
1435 return 1;
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001436out_dec:
1437 atomic_dec(&sdev->device_busy);
1438 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001439}
1440
Mike Christief0c0a372008-08-17 15:24:38 -05001441/*
1442 * scsi_target_queue_ready: checks if there we can send commands to target
1443 * @sdev: scsi device on starget to check.
Mike Christief0c0a372008-08-17 15:24:38 -05001444 */
1445static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1446 struct scsi_device *sdev)
1447{
1448 struct scsi_target *starget = scsi_target(sdev);
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001449 unsigned int busy;
Mike Christief0c0a372008-08-17 15:24:38 -05001450
1451 if (starget->single_lun) {
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001452 spin_lock_irq(shost->host_lock);
Mike Christief0c0a372008-08-17 15:24:38 -05001453 if (starget->starget_sdev_user &&
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001454 starget->starget_sdev_user != sdev) {
1455 spin_unlock_irq(shost->host_lock);
1456 return 0;
1457 }
Mike Christief0c0a372008-08-17 15:24:38 -05001458 starget->starget_sdev_user = sdev;
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001459 spin_unlock_irq(shost->host_lock);
Mike Christief0c0a372008-08-17 15:24:38 -05001460 }
1461
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001462 if (starget->can_queue <= 0)
1463 return 1;
1464
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001465 busy = atomic_inc_return(&starget->target_busy) - 1;
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001466 if (atomic_read(&starget->target_blocked) > 0) {
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001467 if (busy)
1468 goto starved;
1469
Mike Christief0c0a372008-08-17 15:24:38 -05001470 /*
1471 * unblock after target_blocked iterates to zero
1472 */
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001473 if (atomic_dec_return(&starget->target_blocked) > 0)
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001474 goto out_dec;
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001475
1476 SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1477 "unblocking target at zero depth\n"));
Mike Christief0c0a372008-08-17 15:24:38 -05001478 }
1479
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001480 if (busy >= starget->can_queue)
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001481 goto starved;
Mike Christief0c0a372008-08-17 15:24:38 -05001482
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001483 return 1;
1484
1485starved:
1486 spin_lock_irq(shost->host_lock);
1487 list_move_tail(&sdev->starved_entry, &shost->starved_list);
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001488 spin_unlock_irq(shost->host_lock);
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001489out_dec:
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001490 if (starget->can_queue > 0)
1491 atomic_dec(&starget->target_busy);
Christoph Hellwig7ae65c02014-01-22 14:49:41 +01001492 return 0;
Mike Christief0c0a372008-08-17 15:24:38 -05001493}
1494
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495/*
1496 * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1497 * return 0. We must end up running the queue again whenever 0 is
1498 * returned, else IO can hang.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001499 */
1500static inline int scsi_host_queue_ready(struct request_queue *q,
1501 struct Scsi_Host *shost,
1502 struct scsi_device *sdev)
1503{
Christoph Hellwig74665012014-01-22 15:29:29 +01001504 unsigned int busy;
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001505
James Bottomley939647e2005-09-18 15:05:20 -05001506 if (scsi_host_in_recovery(shost))
Christoph Hellwig74665012014-01-22 15:29:29 +01001507 return 0;
1508
1509 busy = atomic_inc_return(&shost->host_busy) - 1;
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001510 if (atomic_read(&shost->host_blocked) > 0) {
Christoph Hellwig74665012014-01-22 15:29:29 +01001511 if (busy)
1512 goto starved;
1513
Linus Torvalds1da177e2005-04-16 15:20:36 -07001514 /*
1515 * unblock after host_blocked iterates to zero
1516 */
Christoph Hellwigcd9070c2014-01-23 12:07:41 +01001517 if (atomic_dec_return(&shost->host_blocked) > 0)
Christoph Hellwig74665012014-01-22 15:29:29 +01001518 goto out_dec;
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001519
1520 SCSI_LOG_MLQUEUE(3,
1521 shost_printk(KERN_INFO, shost,
1522 "unblocking host at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523 }
Christoph Hellwig74665012014-01-22 15:29:29 +01001524
1525 if (shost->can_queue > 0 && busy >= shost->can_queue)
1526 goto starved;
1527 if (shost->host_self_blocked)
1528 goto starved;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001529
1530 /* We're OK to process the command, so we can't be starved */
Christoph Hellwig74665012014-01-22 15:29:29 +01001531 if (!list_empty(&sdev->starved_entry)) {
1532 spin_lock_irq(shost->host_lock);
1533 if (!list_empty(&sdev->starved_entry))
1534 list_del_init(&sdev->starved_entry);
1535 spin_unlock_irq(shost->host_lock);
1536 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001537
Christoph Hellwig74665012014-01-22 15:29:29 +01001538 return 1;
1539
1540starved:
1541 spin_lock_irq(shost->host_lock);
1542 if (list_empty(&sdev->starved_entry))
1543 list_add_tail(&sdev->starved_entry, &shost->starved_list);
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001544 spin_unlock_irq(shost->host_lock);
Christoph Hellwig74665012014-01-22 15:29:29 +01001545out_dec:
1546 atomic_dec(&shost->host_busy);
1547 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001548}
1549
1550/*
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001551 * Busy state exporting function for request stacking drivers.
1552 *
1553 * For efficiency, no lock is taken to check the busy state of
1554 * shost/starget/sdev, since the returned value is not guaranteed and
1555 * may be changed after request stacking drivers call the function,
1556 * regardless of taking lock or not.
1557 *
Bart Van Assche67bd9412012-06-29 15:33:22 +00001558 * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1559 * needs to return 'not busy'. Otherwise, request stacking drivers
1560 * may hold requests forever.
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001561 */
1562static int scsi_lld_busy(struct request_queue *q)
1563{
1564 struct scsi_device *sdev = q->queuedata;
1565 struct Scsi_Host *shost;
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001566
Bart Van Assche3f3299d2012-11-28 13:42:38 +01001567 if (blk_queue_dying(q))
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001568 return 0;
1569
1570 shost = sdev->host;
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001571
Jun'ichi Nomurab7e94a12012-05-22 18:57:17 +09001572 /*
1573 * Ignore host/starget busy state.
1574 * Since block layer does not have a concept of fairness across
1575 * multiple queues, congestion of host/starget needs to be handled
1576 * in SCSI layer.
1577 */
1578 if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04001579 return 1;
1580
1581 return 0;
1582}
1583
1584/*
James Bottomleye91442b2005-09-09 10:44:16 -05001585 * Kill a request for a dead device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001586 */
Jens Axboe165125e2007-07-24 09:28:11 +02001587static void scsi_kill_request(struct request *req, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001588{
James Bottomleye91442b2005-09-09 10:44:16 -05001589 struct scsi_cmnd *cmd = req->special;
Jiri Slaby03b14702009-09-23 16:15:35 +02001590 struct scsi_device *sdev;
1591 struct scsi_target *starget;
1592 struct Scsi_Host *shost;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001593
Tejun Heo9934c8c2009-05-08 11:54:16 +09001594 blk_start_request(req);
James Bottomley788ce432005-09-09 13:40:23 -05001595
Hannes Reinecke74571812011-11-09 08:39:24 +01001596 scmd_printk(KERN_INFO, cmd, "killing request\n");
1597
Jiri Slaby03b14702009-09-23 16:15:35 +02001598 sdev = cmd->device;
1599 starget = scsi_target(sdev);
1600 shost = sdev->host;
James Bottomleye91442b2005-09-09 10:44:16 -05001601 scsi_init_cmd_errh(cmd);
1602 cmd->result = DID_NO_CONNECT << 16;
1603 atomic_inc(&cmd->device->iorequest_cnt);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001604
1605 /*
1606 * SCSI request completion path will do scsi_device_unbusy(),
1607 * bump busy counts. To bump the counters, we need to dance
1608 * with the locks as normal issue path does.
1609 */
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001610 atomic_inc(&sdev->device_busy);
Christoph Hellwig74665012014-01-22 15:29:29 +01001611 atomic_inc(&shost->host_busy);
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001612 if (starget->can_queue > 0)
1613 atomic_inc(&starget->target_busy);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001614
Jens Axboe242f9dc2008-09-14 05:55:09 -07001615 blk_complete_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001616}
1617
Jens Axboe1aea6432006-01-09 16:03:03 +01001618static void scsi_softirq_done(struct request *rq)
1619{
Jens Axboe242f9dc2008-09-14 05:55:09 -07001620 struct scsi_cmnd *cmd = rq->special;
1621 unsigned long wait_for = (cmd->allowed + 1) * rq->timeout;
Jens Axboe1aea6432006-01-09 16:03:03 +01001622 int disposition;
1623
1624 INIT_LIST_HEAD(&cmd->eh_entry);
1625
Jens Axboe242f9dc2008-09-14 05:55:09 -07001626 atomic_inc(&cmd->device->iodone_cnt);
1627 if (cmd->result)
1628 atomic_inc(&cmd->device->ioerr_cnt);
1629
Jens Axboe1aea6432006-01-09 16:03:03 +01001630 disposition = scsi_decide_disposition(cmd);
1631 if (disposition != SUCCESS &&
1632 time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
1633 sdev_printk(KERN_ERR, cmd->device,
1634 "timing out command, waited %lus\n",
1635 wait_for/HZ);
1636 disposition = SUCCESS;
1637 }
Hannes Reinecke91921e02014-06-25 16:39:59 +02001638
Jens Axboe1aea6432006-01-09 16:03:03 +01001639 scsi_log_completion(cmd, disposition);
1640
1641 switch (disposition) {
1642 case SUCCESS:
1643 scsi_finish_command(cmd);
1644 break;
1645 case NEEDS_RETRY:
Christoph Hellwig596f4822007-01-02 12:56:00 +01001646 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
Jens Axboe1aea6432006-01-09 16:03:03 +01001647 break;
1648 case ADD_TO_MLQUEUE:
1649 scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1650 break;
1651 default:
1652 if (!scsi_eh_scmd_add(cmd, 0))
1653 scsi_finish_command(cmd);
1654 }
1655}
1656
Christoph Hellwig3b5382c2014-05-06 12:25:40 +02001657/**
Christoph Hellwig82042a22014-09-05 18:23:07 -07001658 * scsi_dispatch_command - Dispatch a command to the low-level driver.
1659 * @cmd: command block we are dispatching.
1660 *
1661 * Return: nonzero return request was rejected and device's queue needs to be
1662 * plugged.
1663 */
1664static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1665{
1666 struct Scsi_Host *host = cmd->device->host;
1667 int rtn = 0;
1668
1669 atomic_inc(&cmd->device->iorequest_cnt);
1670
1671 /* check if the device is still usable */
1672 if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1673 /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1674 * returns an immediate error upwards, and signals
1675 * that the device is no longer present */
1676 cmd->result = DID_NO_CONNECT << 16;
1677 goto done;
1678 }
1679
1680 /* Check to see if the scsi lld made this device blocked. */
1681 if (unlikely(scsi_device_blocked(cmd->device))) {
1682 /*
1683 * in blocked state, the command is just put back on
1684 * the device queue. The suspend state has already
1685 * blocked the queue so future requests should not
1686 * occur until the device transitions out of the
1687 * suspend state.
1688 */
1689 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1690 "queuecommand : device blocked\n"));
1691 return SCSI_MLQUEUE_DEVICE_BUSY;
1692 }
1693
1694 /* Store the LUN value in cmnd, if needed. */
1695 if (cmd->device->lun_in_cdb)
1696 cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1697 (cmd->device->lun << 5 & 0xe0);
1698
1699 scsi_log_send(cmd);
1700
1701 /*
1702 * Before we queue this command, check if the command
1703 * length exceeds what the host adapter can handle.
1704 */
1705 if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1706 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1707 "queuecommand : command too long. "
1708 "cdb_size=%d host->max_cmd_len=%d\n",
1709 cmd->cmd_len, cmd->device->host->max_cmd_len));
1710 cmd->result = (DID_ABORT << 16);
1711 goto done;
1712 }
1713
1714 if (unlikely(host->shost_state == SHOST_DEL)) {
1715 cmd->result = (DID_NO_CONNECT << 16);
1716 goto done;
1717
1718 }
1719
1720 trace_scsi_dispatch_cmd_start(cmd);
1721 rtn = host->hostt->queuecommand(host, cmd);
1722 if (rtn) {
1723 trace_scsi_dispatch_cmd_error(cmd, rtn);
1724 if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1725 rtn != SCSI_MLQUEUE_TARGET_BUSY)
1726 rtn = SCSI_MLQUEUE_HOST_BUSY;
1727
1728 SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1729 "queuecommand : request rejected\n"));
1730 }
1731
1732 return rtn;
1733 done:
1734 cmd->scsi_done(cmd);
1735 return 0;
1736}
1737
1738/**
Christoph Hellwig3b5382c2014-05-06 12:25:40 +02001739 * scsi_done - Invoke completion on finished SCSI command.
1740 * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
1741 * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
1742 *
1743 * Description: This function is the mid-level's (SCSI Core) interrupt routine,
1744 * which regains ownership of the SCSI command (de facto) from a LLDD, and
1745 * calls blk_complete_request() for further processing.
1746 *
1747 * This function is interrupt context safe.
1748 */
1749static void scsi_done(struct scsi_cmnd *cmd)
1750{
1751 trace_scsi_dispatch_cmd_done(cmd);
1752 blk_complete_request(cmd->request);
1753}
1754
Linus Torvalds1da177e2005-04-16 15:20:36 -07001755/*
1756 * Function: scsi_request_fn()
1757 *
1758 * Purpose: Main strategy routine for SCSI.
1759 *
1760 * Arguments: q - Pointer to actual queue.
1761 *
1762 * Returns: Nothing
1763 *
1764 * Lock status: IO request lock assumed to be held when called.
1765 */
1766static void scsi_request_fn(struct request_queue *q)
Bart Van Assche613be1f2014-02-20 14:20:56 -08001767 __releases(q->queue_lock)
1768 __acquires(q->queue_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001769{
1770 struct scsi_device *sdev = q->queuedata;
1771 struct Scsi_Host *shost;
1772 struct scsi_cmnd *cmd;
1773 struct request *req;
1774
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775 /*
1776 * To start with, we keep looping until the queue is empty, or until
1777 * the host is no longer able to accept any more requests.
1778 */
1779 shost = sdev->host;
Jens Axboea488e742010-04-16 21:13:15 +02001780 for (;;) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001781 int rtn;
1782 /*
1783 * get next queueable request. We do this early to make sure
Hannes Reinecke91921e02014-06-25 16:39:59 +02001784 * that the request is fully prepared even if we cannot
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785 * accept it.
1786 */
Tejun Heo9934c8c2009-05-08 11:54:16 +09001787 req = blk_peek_request(q);
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001788 if (!req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789 break;
1790
1791 if (unlikely(!scsi_device_online(sdev))) {
James Bottomley9ccfc752005-10-02 11:45:08 -05001792 sdev_printk(KERN_ERR, sdev,
1793 "rejecting I/O to offline device\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001794 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795 continue;
1796 }
1797
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001798 if (!scsi_dev_queue_ready(q, sdev))
1799 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001800
1801 /*
1802 * Remove the request from the request list.
1803 */
1804 if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req)))
Tejun Heo9934c8c2009-05-08 11:54:16 +09001805 blk_start_request(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001806
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001807 spin_unlock_irq(q->queue_lock);
James Bottomleye91442b2005-09-09 10:44:16 -05001808 cmd = req->special;
1809 if (unlikely(cmd == NULL)) {
1810 printk(KERN_CRIT "impossible request in %s.\n"
1811 "please mail a stack trace to "
Jens Axboe4aff5e22006-08-10 08:44:47 +02001812 "linux-scsi@vger.kernel.org\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07001813 __func__);
Jens Axboe4aff5e22006-08-10 08:44:47 +02001814 blk_dump_rq_flags(req, "foo");
James Bottomleye91442b2005-09-09 10:44:16 -05001815 BUG();
1816 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001817
Mike Christieecefe8a2008-07-11 19:50:35 -05001818 /*
1819 * We hit this when the driver is using a host wide
1820 * tag map. For device level tag maps the queue_depth check
1821 * in the device ready fn would prevent us from trying
1822 * to allocate a tag. Since the map is a shared host resource
1823 * we add the dev to the starved list so it eventually gets
1824 * a run when a tag is freed.
1825 */
Christoph Hellwig125c99b2014-11-03 12:47:47 +01001826 if (blk_queue_tagged(q) && !(req->cmd_flags & REQ_QUEUED)) {
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001827 spin_lock_irq(shost->host_lock);
Mike Christieecefe8a2008-07-11 19:50:35 -05001828 if (list_empty(&sdev->starved_entry))
1829 list_add_tail(&sdev->starved_entry,
1830 &shost->starved_list);
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001831 spin_unlock_irq(shost->host_lock);
Mike Christieecefe8a2008-07-11 19:50:35 -05001832 goto not_ready;
1833 }
1834
Mike Christief0c0a372008-08-17 15:24:38 -05001835 if (!scsi_target_queue_ready(shost, sdev))
1836 goto not_ready;
1837
Linus Torvalds1da177e2005-04-16 15:20:36 -07001838 if (!scsi_host_queue_ready(q, shost, sdev))
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001839 goto host_not_ready;
Christoph Hellwig125c99b2014-11-03 12:47:47 +01001840
1841 if (sdev->simple_tags)
1842 cmd->flags |= SCMD_TAGGED;
1843 else
1844 cmd->flags &= ~SCMD_TAGGED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845
Linus Torvalds1da177e2005-04-16 15:20:36 -07001846 /*
1847 * Finally, initialize any error handling parameters, and set up
1848 * the timers for timeouts.
1849 */
1850 scsi_init_cmd_errh(cmd);
1851
1852 /*
1853 * Dispatch the command to the low-level driver.
1854 */
Christoph Hellwig3b5382c2014-05-06 12:25:40 +02001855 cmd->scsi_done = scsi_done;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001856 rtn = scsi_dispatch_cmd(cmd);
Christoph Hellwigd0d3bbf2014-01-22 18:39:04 +01001857 if (rtn) {
1858 scsi_queue_insert(cmd, rtn);
1859 spin_lock_irq(q->queue_lock);
Jens Axboea488e742010-04-16 21:13:15 +02001860 goto out_delay;
Christoph Hellwigd0d3bbf2014-01-22 18:39:04 +01001861 }
1862 spin_lock_irq(q->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001863 }
1864
Bart Van Assche613be1f2014-02-20 14:20:56 -08001865 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001867 host_not_ready:
Christoph Hellwig2ccbb002014-03-26 10:35:00 +01001868 if (scsi_target(sdev)->can_queue > 0)
1869 atomic_dec(&scsi_target(sdev)->target_busy);
Christoph Hellwigcf68d332014-01-22 14:36:32 +01001870 not_ready:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001871 /*
1872 * lock q, handle tag, requeue req, and decrement device_busy. We
1873 * must return with queue_lock held.
1874 *
1875 * Decrementing device_busy without checking it is OK, as all such
1876 * cases (host limits or settings) should run the queue at some
1877 * later time.
1878 */
1879 spin_lock_irq(q->queue_lock);
1880 blk_requeue_request(q, req);
Christoph Hellwig71e75c92014-04-11 19:07:01 +02001881 atomic_dec(&sdev->device_busy);
Jens Axboea488e742010-04-16 21:13:15 +02001882out_delay:
Guenter Roeck480cadc2014-08-10 05:54:25 -07001883 if (!atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev))
Jens Axboea488e742010-04-16 21:13:15 +02001884 blk_delay_queue(q, SCSI_QUEUE_DELAY);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885}
1886
Christoph Hellwigd2852032014-01-17 12:06:53 +01001887static inline int prep_to_mq(int ret)
1888{
1889 switch (ret) {
1890 case BLKPREP_OK:
1891 return 0;
1892 case BLKPREP_DEFER:
1893 return BLK_MQ_RQ_QUEUE_BUSY;
1894 default:
1895 return BLK_MQ_RQ_QUEUE_ERROR;
1896 }
1897}
1898
1899static int scsi_mq_prep_fn(struct request *req)
1900{
1901 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1902 struct scsi_device *sdev = req->q->queuedata;
1903 struct Scsi_Host *shost = sdev->host;
1904 unsigned char *sense_buf = cmd->sense_buffer;
1905 struct scatterlist *sg;
1906
1907 memset(cmd, 0, sizeof(struct scsi_cmnd));
1908
1909 req->special = cmd;
1910
1911 cmd->request = req;
1912 cmd->device = sdev;
1913 cmd->sense_buffer = sense_buf;
1914
1915 cmd->tag = req->tag;
1916
Christoph Hellwigd2852032014-01-17 12:06:53 +01001917 cmd->cmnd = req->cmd;
1918 cmd->prot_op = SCSI_PROT_NORMAL;
1919
1920 INIT_LIST_HEAD(&cmd->list);
1921 INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1922 cmd->jiffies_at_alloc = jiffies;
1923
Kashyap.Desai@avagotech.com64bdcbc2014-08-20 19:24:33 +05301924 if (shost->use_cmd_list) {
1925 spin_lock_irq(&sdev->list_lock);
1926 list_add_tail(&cmd->list, &sdev->cmd_list);
1927 spin_unlock_irq(&sdev->list_lock);
1928 }
Christoph Hellwigd2852032014-01-17 12:06:53 +01001929
1930 sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1931 cmd->sdb.table.sgl = sg;
1932
1933 if (scsi_host_get_prot(shost)) {
1934 cmd->prot_sdb = (void *)sg +
Tony Battersby120bb3e2014-12-08 17:20:52 -05001935 min_t(unsigned int,
1936 shost->sg_tablesize, SCSI_MAX_SG_SEGMENTS) *
1937 sizeof(struct scatterlist);
Christoph Hellwigd2852032014-01-17 12:06:53 +01001938 memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1939
1940 cmd->prot_sdb->table.sgl =
1941 (struct scatterlist *)(cmd->prot_sdb + 1);
1942 }
1943
1944 if (blk_bidi_rq(req)) {
1945 struct request *next_rq = req->next_rq;
1946 struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
1947
1948 memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
1949 bidi_sdb->table.sgl =
1950 (struct scatterlist *)(bidi_sdb + 1);
1951
1952 next_rq->special = bidi_sdb;
1953 }
1954
Christoph Hellwigfe052522014-09-22 15:59:31 +02001955 blk_mq_start_request(req);
1956
Christoph Hellwigd2852032014-01-17 12:06:53 +01001957 return scsi_setup_cmnd(sdev, req);
1958}
1959
1960static void scsi_mq_done(struct scsi_cmnd *cmd)
1961{
1962 trace_scsi_dispatch_cmd_done(cmd);
Christoph Hellwigf4829a92015-09-27 21:01:50 +02001963 blk_mq_complete_request(cmd->request, cmd->request->errors);
Christoph Hellwigd2852032014-01-17 12:06:53 +01001964}
1965
Jens Axboe74c45052014-10-29 11:14:52 -06001966static int scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1967 const struct blk_mq_queue_data *bd)
Christoph Hellwigd2852032014-01-17 12:06:53 +01001968{
Jens Axboe74c45052014-10-29 11:14:52 -06001969 struct request *req = bd->rq;
Christoph Hellwigd2852032014-01-17 12:06:53 +01001970 struct request_queue *q = req->q;
1971 struct scsi_device *sdev = q->queuedata;
1972 struct Scsi_Host *shost = sdev->host;
1973 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1974 int ret;
1975 int reason;
1976
1977 ret = prep_to_mq(scsi_prep_state_check(sdev, req));
1978 if (ret)
1979 goto out;
1980
1981 ret = BLK_MQ_RQ_QUEUE_BUSY;
1982 if (!get_device(&sdev->sdev_gendev))
1983 goto out;
1984
1985 if (!scsi_dev_queue_ready(q, sdev))
1986 goto out_put_device;
1987 if (!scsi_target_queue_ready(shost, sdev))
1988 goto out_dec_device_busy;
1989 if (!scsi_host_queue_ready(q, shost, sdev))
1990 goto out_dec_target_busy;
1991
Christoph Hellwigfe052522014-09-22 15:59:31 +02001992
Christoph Hellwigd2852032014-01-17 12:06:53 +01001993 if (!(req->cmd_flags & REQ_DONTPREP)) {
1994 ret = prep_to_mq(scsi_mq_prep_fn(req));
1995 if (ret)
1996 goto out_dec_host_busy;
1997 req->cmd_flags |= REQ_DONTPREP;
Christoph Hellwigfe052522014-09-22 15:59:31 +02001998 } else {
1999 blk_mq_start_request(req);
Christoph Hellwigd2852032014-01-17 12:06:53 +01002000 }
2001
Christoph Hellwig125c99b2014-11-03 12:47:47 +01002002 if (sdev->simple_tags)
2003 cmd->flags |= SCMD_TAGGED;
Christoph Hellwigb1dd2aa2014-10-19 17:13:58 +02002004 else
Christoph Hellwig125c99b2014-11-03 12:47:47 +01002005 cmd->flags &= ~SCMD_TAGGED;
Christoph Hellwigb1dd2aa2014-10-19 17:13:58 +02002006
Christoph Hellwigd2852032014-01-17 12:06:53 +01002007 scsi_init_cmd_errh(cmd);
2008 cmd->scsi_done = scsi_mq_done;
2009
2010 reason = scsi_dispatch_cmd(cmd);
2011 if (reason) {
2012 scsi_set_blocked(cmd, reason);
2013 ret = BLK_MQ_RQ_QUEUE_BUSY;
2014 goto out_dec_host_busy;
2015 }
2016
2017 return BLK_MQ_RQ_QUEUE_OK;
2018
2019out_dec_host_busy:
2020 atomic_dec(&shost->host_busy);
2021out_dec_target_busy:
2022 if (scsi_target(sdev)->can_queue > 0)
2023 atomic_dec(&scsi_target(sdev)->target_busy);
2024out_dec_device_busy:
2025 atomic_dec(&sdev->device_busy);
2026out_put_device:
2027 put_device(&sdev->sdev_gendev);
2028out:
2029 switch (ret) {
2030 case BLK_MQ_RQ_QUEUE_BUSY:
2031 blk_mq_stop_hw_queue(hctx);
2032 if (atomic_read(&sdev->device_busy) == 0 &&
2033 !scsi_device_blocked(sdev))
2034 blk_mq_delay_queue(hctx, SCSI_QUEUE_DELAY);
2035 break;
2036 case BLK_MQ_RQ_QUEUE_ERROR:
2037 /*
2038 * Make sure to release all allocated ressources when
2039 * we hit an error, as we will never see this command
2040 * again.
2041 */
2042 if (req->cmd_flags & REQ_DONTPREP)
2043 scsi_mq_uninit_cmd(cmd);
2044 break;
2045 default:
2046 break;
2047 }
2048 return ret;
2049}
2050
Christoph Hellwig0152fb62014-09-13 16:40:13 -07002051static enum blk_eh_timer_return scsi_timeout(struct request *req,
2052 bool reserved)
2053{
2054 if (reserved)
2055 return BLK_EH_RESET_TIMER;
2056 return scsi_times_out(req);
2057}
2058
Christoph Hellwigd2852032014-01-17 12:06:53 +01002059static int scsi_init_request(void *data, struct request *rq,
2060 unsigned int hctx_idx, unsigned int request_idx,
2061 unsigned int numa_node)
2062{
2063 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2064
2065 cmd->sense_buffer = kzalloc_node(SCSI_SENSE_BUFFERSIZE, GFP_KERNEL,
2066 numa_node);
2067 if (!cmd->sense_buffer)
2068 return -ENOMEM;
2069 return 0;
2070}
2071
2072static void scsi_exit_request(void *data, struct request *rq,
2073 unsigned int hctx_idx, unsigned int request_idx)
2074{
2075 struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
2076
2077 kfree(cmd->sense_buffer);
2078}
2079
Christoph Hellwigf1bea552014-04-15 12:26:54 +02002080static u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002081{
2082 struct device *host_dev;
2083 u64 bounce_limit = 0xffffffff;
2084
2085 if (shost->unchecked_isa_dma)
2086 return BLK_BOUNCE_ISA;
2087 /*
2088 * Platforms with virtual-DMA translation
2089 * hardware have no practical limit.
2090 */
2091 if (!PCI_DMA_BUS_IS_PHYS)
2092 return BLK_BOUNCE_ANY;
2093
2094 host_dev = scsi_get_device(shost);
2095 if (host_dev && host_dev->dma_mask)
Russell Kinge83b3662014-02-11 17:11:04 +00002096 bounce_limit = (u64)dma_max_pfn(host_dev) << PAGE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002097
2098 return bounce_limit;
2099}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002100
Christoph Hellwigd2852032014-01-17 12:06:53 +01002101static void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002102{
Lin Ming6f381fa2012-04-12 13:50:38 +08002103 struct device *dev = shost->dma_dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002104
Jens Axboea8474ce2007-08-07 09:02:51 +02002105 /*
2106 * this limit is imposed by hardware restrictions
2107 */
Martin K. Petersen8a783622010-02-26 00:20:39 -05002108 blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
2109 SCSI_MAX_SG_CHAIN_SEGMENTS));
Jens Axboea8474ce2007-08-07 09:02:51 +02002110
Martin K. Petersen13f05c82010-09-10 20:50:10 +02002111 if (scsi_host_prot_dma(shost)) {
2112 shost->sg_prot_tablesize =
2113 min_not_zero(shost->sg_prot_tablesize,
2114 (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
2115 BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
2116 blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
2117 }
2118
Martin K. Petersen086fa5f2010-02-26 00:20:38 -05002119 blk_queue_max_hw_sectors(q, shost->max_sectors);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002120 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
2121 blk_queue_segment_boundary(q, shost->dma_boundary);
FUJITA Tomonori99c84db2008-02-04 22:28:17 -08002122 dma_set_seg_boundary(dev, shost->dma_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002123
FUJITA Tomonori860ac562008-02-04 22:28:05 -08002124 blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
2125
Linus Torvalds1da177e2005-04-16 15:20:36 -07002126 if (!shost->use_clustering)
Martin K. Petersene692cb62010-12-01 19:41:49 +01002127 q->limits.cluster = 0;
James Bottomley465ff312008-01-01 10:00:10 -06002128
2129 /*
2130 * set a reasonable default alignment on word boundaries: the
2131 * host and device may alter it using
2132 * blk_queue_update_dma_alignment() later.
2133 */
2134 blk_queue_dma_alignment(q, 0x03);
Christoph Hellwigd2852032014-01-17 12:06:53 +01002135}
James Bottomley465ff312008-01-01 10:00:10 -06002136
Christoph Hellwigd2852032014-01-17 12:06:53 +01002137struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
2138 request_fn_proc *request_fn)
2139{
2140 struct request_queue *q;
2141
2142 q = blk_init_queue(request_fn, NULL);
2143 if (!q)
2144 return NULL;
2145 __scsi_init_queue(shost, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002146 return q;
2147}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09002148EXPORT_SYMBOL(__scsi_alloc_queue);
2149
2150struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
2151{
2152 struct request_queue *q;
2153
2154 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
2155 if (!q)
2156 return NULL;
2157
2158 blk_queue_prep_rq(q, scsi_prep_fn);
Christoph Hellwiga1b73fc2014-05-01 16:51:04 +02002159 blk_queue_unprep_rq(q, scsi_unprep_fn);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09002160 blk_queue_softirq_done(q, scsi_softirq_done);
Jens Axboe242f9dc2008-09-14 05:55:09 -07002161 blk_queue_rq_timed_out(q, scsi_times_out);
Kiyoshi Ueda6c5121b2008-10-04 14:11:35 -04002162 blk_queue_lld_busy(q, scsi_lld_busy);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09002163 return q;
2164}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002165
Christoph Hellwigd2852032014-01-17 12:06:53 +01002166static struct blk_mq_ops scsi_mq_ops = {
2167 .map_queue = blk_mq_map_queue,
2168 .queue_rq = scsi_queue_rq,
2169 .complete = scsi_softirq_done,
Christoph Hellwig0152fb62014-09-13 16:40:13 -07002170 .timeout = scsi_timeout,
Christoph Hellwigd2852032014-01-17 12:06:53 +01002171 .init_request = scsi_init_request,
2172 .exit_request = scsi_exit_request,
2173};
2174
2175struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
2176{
2177 sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
2178 if (IS_ERR(sdev->request_queue))
2179 return NULL;
2180
2181 sdev->request_queue->queuedata = sdev;
2182 __scsi_init_queue(sdev->host, sdev->request_queue);
2183 return sdev->request_queue;
2184}
2185
2186int scsi_mq_setup_tags(struct Scsi_Host *shost)
2187{
2188 unsigned int cmd_size, sgl_size, tbl_size;
2189
2190 tbl_size = shost->sg_tablesize;
2191 if (tbl_size > SCSI_MAX_SG_SEGMENTS)
2192 tbl_size = SCSI_MAX_SG_SEGMENTS;
2193 sgl_size = tbl_size * sizeof(struct scatterlist);
2194 cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
2195 if (scsi_host_get_prot(shost))
2196 cmd_size += sizeof(struct scsi_data_buffer) + sgl_size;
2197
2198 memset(&shost->tag_set, 0, sizeof(shost->tag_set));
2199 shost->tag_set.ops = &scsi_mq_ops;
Bart Van Asscheefec4b92014-10-30 14:45:36 +01002200 shost->tag_set.nr_hw_queues = shost->nr_hw_queues ? : 1;
Christoph Hellwigd2852032014-01-17 12:06:53 +01002201 shost->tag_set.queue_depth = shost->can_queue;
2202 shost->tag_set.cmd_size = cmd_size;
2203 shost->tag_set.numa_node = NUMA_NO_NODE;
2204 shost->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
Shaohua Li24391c02015-01-23 14:18:00 -07002205 shost->tag_set.flags |=
2206 BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
Christoph Hellwigd2852032014-01-17 12:06:53 +01002207 shost->tag_set.driver_data = shost;
2208
2209 return blk_mq_alloc_tag_set(&shost->tag_set);
2210}
2211
2212void scsi_mq_destroy_tags(struct Scsi_Host *shost)
2213{
2214 blk_mq_free_tag_set(&shost->tag_set);
2215}
2216
Linus Torvalds1da177e2005-04-16 15:20:36 -07002217/*
2218 * Function: scsi_block_requests()
2219 *
2220 * Purpose: Utility function used by low-level drivers to prevent further
2221 * commands from being queued to the device.
2222 *
2223 * Arguments: shost - Host in question
2224 *
2225 * Returns: Nothing
2226 *
2227 * Lock status: No locks are assumed held.
2228 *
2229 * Notes: There is no timer nor any other means by which the requests
2230 * get unblocked other than the low-level driver calling
2231 * scsi_unblock_requests().
2232 */
2233void scsi_block_requests(struct Scsi_Host *shost)
2234{
2235 shost->host_self_blocked = 1;
2236}
2237EXPORT_SYMBOL(scsi_block_requests);
2238
2239/*
2240 * Function: scsi_unblock_requests()
2241 *
2242 * Purpose: Utility function used by low-level drivers to allow further
2243 * commands from being queued to the device.
2244 *
2245 * Arguments: shost - Host in question
2246 *
2247 * Returns: Nothing
2248 *
2249 * Lock status: No locks are assumed held.
2250 *
2251 * Notes: There is no timer nor any other means by which the requests
2252 * get unblocked other than the low-level driver calling
2253 * scsi_unblock_requests().
2254 *
2255 * This is done as an API function so that changes to the
2256 * internals of the scsi mid-layer won't require wholesale
2257 * changes to drivers that use this feature.
2258 */
2259void scsi_unblock_requests(struct Scsi_Host *shost)
2260{
2261 shost->host_self_blocked = 0;
2262 scsi_run_host_queues(shost);
2263}
2264EXPORT_SYMBOL(scsi_unblock_requests);
2265
2266int __init scsi_init_queue(void)
2267{
2268 int i;
2269
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002270 scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
2271 sizeof(struct scsi_data_buffer),
2272 0, 0, NULL);
2273 if (!scsi_sdb_cache) {
2274 printk(KERN_ERR "SCSI: can't init scsi sdb cache\n");
FUJITA Tomonorif0787272008-12-14 01:23:45 +09002275 return -ENOMEM;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02002276 }
2277
Linus Torvalds1da177e2005-04-16 15:20:36 -07002278 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2279 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2280 int size = sgp->size * sizeof(struct scatterlist);
2281
2282 sgp->slab = kmem_cache_create(sgp->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09002283 SLAB_HWCACHE_ALIGN, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002284 if (!sgp->slab) {
2285 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
2286 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002287 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002288 }
2289
Matthew Dobson93d23412006-03-26 01:37:50 -08002290 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
2291 sgp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002292 if (!sgp->pool) {
2293 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
2294 sgp->name);
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002295 goto cleanup_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002296 }
2297 }
2298
2299 return 0;
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09002300
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002301cleanup_sdb:
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09002302 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2303 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2304 if (sgp->pool)
2305 mempool_destroy(sgp->pool);
2306 if (sgp->slab)
2307 kmem_cache_destroy(sgp->slab);
2308 }
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002309 kmem_cache_destroy(scsi_sdb_cache);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09002310
2311 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002312}
2313
2314void scsi_exit_queue(void)
2315{
2316 int i;
2317
Martin K. Petersen6362abd2008-06-05 23:30:03 -04002318 kmem_cache_destroy(scsi_sdb_cache);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06002319
Linus Torvalds1da177e2005-04-16 15:20:36 -07002320 for (i = 0; i < SG_MEMPOOL_NR; i++) {
2321 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
2322 mempool_destroy(sgp->pool);
2323 kmem_cache_destroy(sgp->slab);
2324 }
2325}
James Bottomley5baba832006-03-18 14:10:35 -06002326
2327/**
2328 * scsi_mode_select - issue a mode select
2329 * @sdev: SCSI device to be queried
2330 * @pf: Page format bit (1 == standard, 0 == vendor specific)
2331 * @sp: Save page bit (0 == don't save, 1 == save)
2332 * @modepage: mode page being requested
2333 * @buffer: request buffer (may not be smaller than eight bytes)
2334 * @len: length of request buffer.
2335 * @timeout: command timeout
2336 * @retries: number of retries before failing
2337 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05002338 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley5baba832006-03-18 14:10:35 -06002339 * must be SCSI_SENSE_BUFFERSIZE big.
2340 *
2341 * Returns zero if successful; negative error number or scsi
2342 * status on error
2343 *
2344 */
2345int
2346scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2347 unsigned char *buffer, int len, int timeout, int retries,
2348 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2349{
2350 unsigned char cmd[10];
2351 unsigned char *real_buffer;
2352 int ret;
2353
2354 memset(cmd, 0, sizeof(cmd));
2355 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2356
2357 if (sdev->use_10_for_ms) {
2358 if (len > 65535)
2359 return -EINVAL;
2360 real_buffer = kmalloc(8 + len, GFP_KERNEL);
2361 if (!real_buffer)
2362 return -ENOMEM;
2363 memcpy(real_buffer + 8, buffer, len);
2364 len += 8;
2365 real_buffer[0] = 0;
2366 real_buffer[1] = 0;
2367 real_buffer[2] = data->medium_type;
2368 real_buffer[3] = data->device_specific;
2369 real_buffer[4] = data->longlba ? 0x01 : 0;
2370 real_buffer[5] = 0;
2371 real_buffer[6] = data->block_descriptor_length >> 8;
2372 real_buffer[7] = data->block_descriptor_length;
2373
2374 cmd[0] = MODE_SELECT_10;
2375 cmd[7] = len >> 8;
2376 cmd[8] = len;
2377 } else {
2378 if (len > 255 || data->block_descriptor_length > 255 ||
2379 data->longlba)
2380 return -EINVAL;
2381
2382 real_buffer = kmalloc(4 + len, GFP_KERNEL);
2383 if (!real_buffer)
2384 return -ENOMEM;
2385 memcpy(real_buffer + 4, buffer, len);
2386 len += 4;
2387 real_buffer[0] = 0;
2388 real_buffer[1] = data->medium_type;
2389 real_buffer[2] = data->device_specific;
2390 real_buffer[3] = data->block_descriptor_length;
2391
2392
2393 cmd[0] = MODE_SELECT;
2394 cmd[4] = len;
2395 }
2396
2397 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002398 sshdr, timeout, retries, NULL);
James Bottomley5baba832006-03-18 14:10:35 -06002399 kfree(real_buffer);
2400 return ret;
2401}
2402EXPORT_SYMBOL_GPL(scsi_mode_select);
2403
Linus Torvalds1da177e2005-04-16 15:20:36 -07002404/**
Rob Landleyeb448202007-11-03 13:30:39 -05002405 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
James Bottomley1cf72692005-08-28 11:27:01 -05002406 * @sdev: SCSI device to be queried
Linus Torvalds1da177e2005-04-16 15:20:36 -07002407 * @dbd: set if mode sense will allow block descriptors to be returned
2408 * @modepage: mode page being requested
2409 * @buffer: request buffer (may not be smaller than eight bytes)
2410 * @len: length of request buffer.
2411 * @timeout: command timeout
2412 * @retries: number of retries before failing
2413 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05002414 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley1cf72692005-08-28 11:27:01 -05002415 * must be SCSI_SENSE_BUFFERSIZE big.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002416 *
2417 * Returns zero if unsuccessful, or the header offset (either 4
2418 * or 8 depending on whether a six or ten byte command was
2419 * issued) if successful.
Rob Landleyeb448202007-11-03 13:30:39 -05002420 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002421int
James Bottomley1cf72692005-08-28 11:27:01 -05002422scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002423 unsigned char *buffer, int len, int timeout, int retries,
James Bottomley5baba832006-03-18 14:10:35 -06002424 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2425{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002426 unsigned char cmd[12];
2427 int use_10_for_ms;
2428 int header_length;
Hannes Reinecke0ae80ba2015-06-12 16:12:48 +02002429 int result, retry_count = retries;
James Bottomleyea73a9f2005-08-28 11:33:52 -05002430 struct scsi_sense_hdr my_sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002431
2432 memset(data, 0, sizeof(*data));
2433 memset(&cmd[0], 0, 12);
2434 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2435 cmd[2] = modepage;
2436
James Bottomleyea73a9f2005-08-28 11:33:52 -05002437 /* caller might not be interested in sense, but we need it */
2438 if (!sshdr)
2439 sshdr = &my_sshdr;
2440
Linus Torvalds1da177e2005-04-16 15:20:36 -07002441 retry:
James Bottomley1cf72692005-08-28 11:27:01 -05002442 use_10_for_ms = sdev->use_10_for_ms;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002443
2444 if (use_10_for_ms) {
2445 if (len < 8)
2446 len = 8;
2447
2448 cmd[0] = MODE_SENSE_10;
2449 cmd[8] = len;
2450 header_length = 8;
2451 } else {
2452 if (len < 4)
2453 len = 4;
2454
2455 cmd[0] = MODE_SENSE;
2456 cmd[4] = len;
2457 header_length = 4;
2458 }
2459
Linus Torvalds1da177e2005-04-16 15:20:36 -07002460 memset(buffer, 0, len);
2461
James Bottomley1cf72692005-08-28 11:27:01 -05002462 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002463 sshdr, timeout, retries, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002464
2465 /* This code looks awful: what it's doing is making sure an
2466 * ILLEGAL REQUEST sense return identifies the actual command
2467 * byte as the problem. MODE_SENSE commands can return
2468 * ILLEGAL REQUEST if the code page isn't supported */
2469
James Bottomley1cf72692005-08-28 11:27:01 -05002470 if (use_10_for_ms && !scsi_status_is_good(result) &&
2471 (driver_byte(result) & DRIVER_SENSE)) {
James Bottomleyea73a9f2005-08-28 11:33:52 -05002472 if (scsi_sense_valid(sshdr)) {
2473 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2474 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002475 /*
2476 * Invalid command operation code
2477 */
James Bottomley1cf72692005-08-28 11:27:01 -05002478 sdev->use_10_for_ms = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002479 goto retry;
2480 }
2481 }
2482 }
2483
James Bottomley1cf72692005-08-28 11:27:01 -05002484 if(scsi_status_is_good(result)) {
Al Viro6d73c852006-02-23 02:03:16 +01002485 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2486 (modepage == 6 || modepage == 8))) {
2487 /* Initio breakage? */
2488 header_length = 0;
2489 data->length = 13;
2490 data->medium_type = 0;
2491 data->device_specific = 0;
2492 data->longlba = 0;
2493 data->block_descriptor_length = 0;
2494 } else if(use_10_for_ms) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002495 data->length = buffer[0]*256 + buffer[1] + 2;
2496 data->medium_type = buffer[2];
2497 data->device_specific = buffer[3];
2498 data->longlba = buffer[4] & 0x01;
2499 data->block_descriptor_length = buffer[6]*256
2500 + buffer[7];
2501 } else {
2502 data->length = buffer[0] + 1;
2503 data->medium_type = buffer[1];
2504 data->device_specific = buffer[2];
2505 data->block_descriptor_length = buffer[3];
2506 }
Al Viro6d73c852006-02-23 02:03:16 +01002507 data->header_length = header_length;
Hannes Reinecke0ae80ba2015-06-12 16:12:48 +02002508 } else if ((status_byte(result) == CHECK_CONDITION) &&
2509 scsi_sense_valid(sshdr) &&
2510 sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2511 retry_count--;
2512 goto retry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002513 }
2514
James Bottomley1cf72692005-08-28 11:27:01 -05002515 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002516}
2517EXPORT_SYMBOL(scsi_mode_sense);
2518
James Bottomley001aac22007-12-02 19:10:40 +02002519/**
2520 * scsi_test_unit_ready - test if unit is ready
2521 * @sdev: scsi device to change the state of.
2522 * @timeout: command timeout
2523 * @retries: number of retries before failing
2524 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
2525 * returning sense. Make sure that this is cleared before passing
2526 * in.
2527 *
2528 * Returns zero if unsuccessful or an error if TUR failed. For
Tejun Heo9f8a2c22010-12-08 20:57:40 +01002529 * removable media, UNIT_ATTENTION sets ->changed flag.
James Bottomley001aac22007-12-02 19:10:40 +02002530 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -07002531int
James Bottomley001aac22007-12-02 19:10:40 +02002532scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2533 struct scsi_sense_hdr *sshdr_external)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002534{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002535 char cmd[] = {
2536 TEST_UNIT_READY, 0, 0, 0, 0, 0,
2537 };
James Bottomley001aac22007-12-02 19:10:40 +02002538 struct scsi_sense_hdr *sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002539 int result;
James Bottomley001aac22007-12-02 19:10:40 +02002540
2541 if (!sshdr_external)
2542 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
2543 else
2544 sshdr = sshdr_external;
2545
2546 /* try to eat the UNIT_ATTENTION if there are enough retries */
2547 do {
2548 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
FUJITA Tomonorif4f4e472008-12-04 14:24:39 +09002549 timeout, retries, NULL);
James Bottomley32c356d2008-08-20 00:58:13 +02002550 if (sdev->removable && scsi_sense_valid(sshdr) &&
2551 sshdr->sense_key == UNIT_ATTENTION)
2552 sdev->changed = 1;
2553 } while (scsi_sense_valid(sshdr) &&
2554 sshdr->sense_key == UNIT_ATTENTION && --retries);
James Bottomley001aac22007-12-02 19:10:40 +02002555
James Bottomley001aac22007-12-02 19:10:40 +02002556 if (!sshdr_external)
2557 kfree(sshdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002558 return result;
2559}
2560EXPORT_SYMBOL(scsi_test_unit_ready);
2561
2562/**
Rob Landleyeb448202007-11-03 13:30:39 -05002563 * scsi_device_set_state - Take the given device through the device state model.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002564 * @sdev: scsi device to change the state of.
2565 * @state: state to change to.
2566 *
2567 * Returns zero if unsuccessful or an error if the requested
2568 * transition is illegal.
Rob Landleyeb448202007-11-03 13:30:39 -05002569 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002570int
2571scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2572{
2573 enum scsi_device_state oldstate = sdev->sdev_state;
2574
2575 if (state == oldstate)
2576 return 0;
2577
2578 switch (state) {
2579 case SDEV_CREATED:
James Bottomley6f4267e2008-08-22 16:53:31 -05002580 switch (oldstate) {
2581 case SDEV_CREATED_BLOCK:
2582 break;
2583 default:
2584 goto illegal;
2585 }
2586 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002587
2588 case SDEV_RUNNING:
2589 switch (oldstate) {
2590 case SDEV_CREATED:
2591 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002592 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002593 case SDEV_QUIESCE:
2594 case SDEV_BLOCK:
2595 break;
2596 default:
2597 goto illegal;
2598 }
2599 break;
2600
2601 case SDEV_QUIESCE:
2602 switch (oldstate) {
2603 case SDEV_RUNNING:
2604 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002605 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002606 break;
2607 default:
2608 goto illegal;
2609 }
2610 break;
2611
2612 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002613 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002614 switch (oldstate) {
2615 case SDEV_CREATED:
2616 case SDEV_RUNNING:
2617 case SDEV_QUIESCE:
2618 case SDEV_BLOCK:
2619 break;
2620 default:
2621 goto illegal;
2622 }
2623 break;
2624
2625 case SDEV_BLOCK:
2626 switch (oldstate) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002627 case SDEV_RUNNING:
James Bottomley6f4267e2008-08-22 16:53:31 -05002628 case SDEV_CREATED_BLOCK:
2629 break;
2630 default:
2631 goto illegal;
2632 }
2633 break;
2634
2635 case SDEV_CREATED_BLOCK:
2636 switch (oldstate) {
2637 case SDEV_CREATED:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002638 break;
2639 default:
2640 goto illegal;
2641 }
2642 break;
2643
2644 case SDEV_CANCEL:
2645 switch (oldstate) {
2646 case SDEV_CREATED:
2647 case SDEV_RUNNING:
Alan Stern9ea72902006-06-23 14:25:34 -04002648 case SDEV_QUIESCE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002649 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002650 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002651 case SDEV_BLOCK:
2652 break;
2653 default:
2654 goto illegal;
2655 }
2656 break;
2657
2658 case SDEV_DEL:
2659 switch (oldstate) {
Brian King309bd272006-06-27 11:10:43 -05002660 case SDEV_CREATED:
2661 case SDEV_RUNNING:
2662 case SDEV_OFFLINE:
Mike Christie1b8d2622012-05-17 23:56:56 -05002663 case SDEV_TRANSPORT_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002664 case SDEV_CANCEL:
Bart Van Assche0516c082013-07-02 15:06:33 +02002665 case SDEV_CREATED_BLOCK:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002666 break;
2667 default:
2668 goto illegal;
2669 }
2670 break;
2671
2672 }
2673 sdev->sdev_state = state;
2674 return 0;
2675
2676 illegal:
Hannes Reinecke91921e02014-06-25 16:39:59 +02002677 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -05002678 sdev_printk(KERN_ERR, sdev,
Hannes Reinecke91921e02014-06-25 16:39:59 +02002679 "Illegal state transition %s->%s",
James Bottomley9ccfc752005-10-02 11:45:08 -05002680 scsi_device_state_name(oldstate),
2681 scsi_device_state_name(state))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002682 );
2683 return -EINVAL;
2684}
2685EXPORT_SYMBOL(scsi_device_set_state);
2686
2687/**
Jeff Garzika341cd02007-10-29 17:15:22 -04002688 * sdev_evt_emit - emit a single SCSI device uevent
2689 * @sdev: associated SCSI device
2690 * @evt: event to emit
2691 *
2692 * Send a single uevent (scsi_event) to the associated scsi_device.
2693 */
2694static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2695{
2696 int idx = 0;
2697 char *envp[3];
2698
2699 switch (evt->evt_type) {
2700 case SDEV_EVT_MEDIA_CHANGE:
2701 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2702 break;
Ewan D. Milne279afdf2013-08-08 15:07:48 -04002703 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2704 envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2705 break;
2706 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2707 envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2708 break;
2709 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2710 envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2711 break;
2712 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2713 envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2714 break;
2715 case SDEV_EVT_LUN_CHANGE_REPORTED:
2716 envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2717 break;
Hannes Reinecke14c3e672015-07-06 13:41:53 +02002718 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2719 envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2720 break;
Jeff Garzika341cd02007-10-29 17:15:22 -04002721 default:
2722 /* do nothing */
2723 break;
2724 }
2725
2726 envp[idx++] = NULL;
2727
2728 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2729}
2730
2731/**
2732 * sdev_evt_thread - send a uevent for each scsi event
2733 * @work: work struct for scsi_device
2734 *
2735 * Dispatch queued events to their associated scsi_device kobjects
2736 * as uevents.
2737 */
2738void scsi_evt_thread(struct work_struct *work)
2739{
2740 struct scsi_device *sdev;
Ewan D. Milne279afdf2013-08-08 15:07:48 -04002741 enum scsi_device_event evt_type;
Jeff Garzika341cd02007-10-29 17:15:22 -04002742 LIST_HEAD(event_list);
2743
2744 sdev = container_of(work, struct scsi_device, event_work);
2745
Ewan D. Milne279afdf2013-08-08 15:07:48 -04002746 for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2747 if (test_and_clear_bit(evt_type, sdev->pending_events))
2748 sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2749
Jeff Garzika341cd02007-10-29 17:15:22 -04002750 while (1) {
2751 struct scsi_event *evt;
2752 struct list_head *this, *tmp;
2753 unsigned long flags;
2754
2755 spin_lock_irqsave(&sdev->list_lock, flags);
2756 list_splice_init(&sdev->event_list, &event_list);
2757 spin_unlock_irqrestore(&sdev->list_lock, flags);
2758
2759 if (list_empty(&event_list))
2760 break;
2761
2762 list_for_each_safe(this, tmp, &event_list) {
2763 evt = list_entry(this, struct scsi_event, node);
2764 list_del(&evt->node);
2765 scsi_evt_emit(sdev, evt);
2766 kfree(evt);
2767 }
2768 }
2769}
2770
2771/**
2772 * sdev_evt_send - send asserted event to uevent thread
2773 * @sdev: scsi_device event occurred on
2774 * @evt: event to send
2775 *
2776 * Assert scsi device event asynchronously.
2777 */
2778void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2779{
2780 unsigned long flags;
2781
Kay Sievers4d1566e2008-03-19 13:04:47 +01002782#if 0
2783 /* FIXME: currently this check eliminates all media change events
2784 * for polled devices. Need to update to discriminate between AN
2785 * and polled events */
Jeff Garzika341cd02007-10-29 17:15:22 -04002786 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2787 kfree(evt);
2788 return;
2789 }
Kay Sievers4d1566e2008-03-19 13:04:47 +01002790#endif
Jeff Garzika341cd02007-10-29 17:15:22 -04002791
2792 spin_lock_irqsave(&sdev->list_lock, flags);
2793 list_add_tail(&evt->node, &sdev->event_list);
2794 schedule_work(&sdev->event_work);
2795 spin_unlock_irqrestore(&sdev->list_lock, flags);
2796}
2797EXPORT_SYMBOL_GPL(sdev_evt_send);
2798
2799/**
2800 * sdev_evt_alloc - allocate a new scsi event
2801 * @evt_type: type of event to allocate
2802 * @gfpflags: GFP flags for allocation
2803 *
2804 * Allocates and returns a new scsi_event.
2805 */
2806struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2807 gfp_t gfpflags)
2808{
2809 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2810 if (!evt)
2811 return NULL;
2812
2813 evt->evt_type = evt_type;
2814 INIT_LIST_HEAD(&evt->node);
2815
2816 /* evt_type-specific initialization, if any */
2817 switch (evt_type) {
2818 case SDEV_EVT_MEDIA_CHANGE:
Ewan D. Milne279afdf2013-08-08 15:07:48 -04002819 case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2820 case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2821 case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2822 case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2823 case SDEV_EVT_LUN_CHANGE_REPORTED:
Hannes Reinecke14c3e672015-07-06 13:41:53 +02002824 case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
Jeff Garzika341cd02007-10-29 17:15:22 -04002825 default:
2826 /* do nothing */
2827 break;
2828 }
2829
2830 return evt;
2831}
2832EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2833
2834/**
2835 * sdev_evt_send_simple - send asserted event to uevent thread
2836 * @sdev: scsi_device event occurred on
2837 * @evt_type: type of event to send
2838 * @gfpflags: GFP flags for allocation
2839 *
2840 * Assert scsi device event asynchronously, given an event type.
2841 */
2842void sdev_evt_send_simple(struct scsi_device *sdev,
2843 enum scsi_device_event evt_type, gfp_t gfpflags)
2844{
2845 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2846 if (!evt) {
2847 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2848 evt_type);
2849 return;
2850 }
2851
2852 sdev_evt_send(sdev, evt);
2853}
2854EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2855
2856/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002857 * scsi_device_quiesce - Block user issued commands.
2858 * @sdev: scsi device to quiesce.
2859 *
2860 * This works by trying to transition to the SDEV_QUIESCE state
2861 * (which must be a legal transition). When the device is in this
2862 * state, only special requests will be accepted, all others will
2863 * be deferred. Since special requests may also be requeued requests,
2864 * a successful return doesn't guarantee the device will be
2865 * totally quiescent.
2866 *
2867 * Must be called with user context, may sleep.
2868 *
2869 * Returns zero if unsuccessful or an error if not.
Rob Landleyeb448202007-11-03 13:30:39 -05002870 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002871int
2872scsi_device_quiesce(struct scsi_device *sdev)
2873{
2874 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2875 if (err)
2876 return err;
2877
2878 scsi_run_queue(sdev->request_queue);
Christoph Hellwig71e75c92014-04-11 19:07:01 +02002879 while (atomic_read(&sdev->device_busy)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002880 msleep_interruptible(200);
2881 scsi_run_queue(sdev->request_queue);
2882 }
2883 return 0;
2884}
2885EXPORT_SYMBOL(scsi_device_quiesce);
2886
2887/**
2888 * scsi_device_resume - Restart user issued commands to a quiesced device.
2889 * @sdev: scsi device to resume.
2890 *
2891 * Moves the device from quiesced back to running and restarts the
2892 * queues.
2893 *
2894 * Must be called with user context, may sleep.
Rob Landleyeb448202007-11-03 13:30:39 -05002895 */
Dan Williamsa7a20d12012-03-22 17:05:11 -07002896void scsi_device_resume(struct scsi_device *sdev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002897{
Dan Williamsa7a20d12012-03-22 17:05:11 -07002898 /* check if the device state was mutated prior to resume, and if
2899 * so assume the state is being managed elsewhere (for example
2900 * device deleted during suspend)
2901 */
2902 if (sdev->sdev_state != SDEV_QUIESCE ||
2903 scsi_device_set_state(sdev, SDEV_RUNNING))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002904 return;
2905 scsi_run_queue(sdev->request_queue);
2906}
2907EXPORT_SYMBOL(scsi_device_resume);
2908
2909static void
2910device_quiesce_fn(struct scsi_device *sdev, void *data)
2911{
2912 scsi_device_quiesce(sdev);
2913}
2914
2915void
2916scsi_target_quiesce(struct scsi_target *starget)
2917{
2918 starget_for_each_device(starget, NULL, device_quiesce_fn);
2919}
2920EXPORT_SYMBOL(scsi_target_quiesce);
2921
2922static void
2923device_resume_fn(struct scsi_device *sdev, void *data)
2924{
2925 scsi_device_resume(sdev);
2926}
2927
2928void
2929scsi_target_resume(struct scsi_target *starget)
2930{
2931 starget_for_each_device(starget, NULL, device_resume_fn);
2932}
2933EXPORT_SYMBOL(scsi_target_resume);
2934
2935/**
Rob Landleyeb448202007-11-03 13:30:39 -05002936 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
Linus Torvalds1da177e2005-04-16 15:20:36 -07002937 * @sdev: device to block
2938 *
2939 * Block request made by scsi lld's to temporarily stop all
2940 * scsi commands on the specified device. Called from interrupt
2941 * or normal process context.
2942 *
2943 * Returns zero if successful or error if not
2944 *
2945 * Notes:
2946 * This routine transitions the device to the SDEV_BLOCK state
2947 * (which must be a legal transition). When the device is in this
2948 * state, all commands are deferred until the scsi lld reenables
2949 * the device with scsi_device_unblock or device_block_tmo fires.
Rob Landleyeb448202007-11-03 13:30:39 -05002950 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002951int
2952scsi_internal_device_block(struct scsi_device *sdev)
2953{
Jens Axboe165125e2007-07-24 09:28:11 +02002954 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002955 unsigned long flags;
2956 int err = 0;
2957
2958 err = scsi_device_set_state(sdev, SDEV_BLOCK);
James Bottomley6f4267e2008-08-22 16:53:31 -05002959 if (err) {
2960 err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2961
2962 if (err)
2963 return err;
2964 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002965
2966 /*
2967 * The device has transitioned to SDEV_BLOCK. Stop the
2968 * block layer from calling the midlayer with this device's
2969 * request queue.
2970 */
Christoph Hellwigd2852032014-01-17 12:06:53 +01002971 if (q->mq_ops) {
2972 blk_mq_stop_hw_queues(q);
2973 } else {
2974 spin_lock_irqsave(q->queue_lock, flags);
2975 blk_stop_queue(q);
2976 spin_unlock_irqrestore(q->queue_lock, flags);
2977 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002978
2979 return 0;
2980}
2981EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2982
2983/**
2984 * scsi_internal_device_unblock - resume a device after a block request
2985 * @sdev: device to resume
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002986 * @new_state: state to set devices to after unblocking
Linus Torvalds1da177e2005-04-16 15:20:36 -07002987 *
2988 * Called by scsi lld's or the midlayer to restart the device queue
2989 * for the previously suspended scsi device. Called from interrupt or
2990 * normal process context.
2991 *
2992 * Returns zero if successful or error if not.
2993 *
2994 * Notes:
2995 * This routine transitions the device to the SDEV_RUNNING state
Mike Christie5d9fb5c2012-05-17 23:56:57 -05002996 * or to one of the offline states (which must be a legal transition)
Mike Christied0754982012-05-17 23:56:58 -05002997 * allowing the midlayer to goose the queue for this device.
Rob Landleyeb448202007-11-03 13:30:39 -05002998 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002999int
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003000scsi_internal_device_unblock(struct scsi_device *sdev,
3001 enum scsi_device_state new_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003002{
Jens Axboe165125e2007-07-24 09:28:11 +02003003 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003004 unsigned long flags;
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003005
3006 /*
3007 * Try to transition the scsi device to SDEV_RUNNING or one of the
3008 * offlined states and goose the device queue if successful.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003009 */
Vikas Chaudhary0e580762012-08-09 04:51:30 -04003010 if ((sdev->sdev_state == SDEV_BLOCK) ||
3011 (sdev->sdev_state == SDEV_TRANSPORT_OFFLINE))
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003012 sdev->sdev_state = new_state;
3013 else if (sdev->sdev_state == SDEV_CREATED_BLOCK) {
3014 if (new_state == SDEV_TRANSPORT_OFFLINE ||
3015 new_state == SDEV_OFFLINE)
3016 sdev->sdev_state = new_state;
3017 else
3018 sdev->sdev_state = SDEV_CREATED;
3019 } else if (sdev->sdev_state != SDEV_CANCEL &&
Mike Christie986fe6c2010-10-06 03:10:59 -05003020 sdev->sdev_state != SDEV_OFFLINE)
Takahiro Yasui5c10e632009-04-29 12:13:02 -04003021 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003022
Christoph Hellwigd2852032014-01-17 12:06:53 +01003023 if (q->mq_ops) {
3024 blk_mq_start_stopped_hw_queues(q, false);
3025 } else {
3026 spin_lock_irqsave(q->queue_lock, flags);
3027 blk_start_queue(q);
3028 spin_unlock_irqrestore(q->queue_lock, flags);
3029 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07003030
3031 return 0;
3032}
3033EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
3034
3035static void
3036device_block(struct scsi_device *sdev, void *data)
3037{
3038 scsi_internal_device_block(sdev);
3039}
3040
3041static int
3042target_block(struct device *dev, void *data)
3043{
3044 if (scsi_is_target_device(dev))
3045 starget_for_each_device(to_scsi_target(dev), NULL,
3046 device_block);
3047 return 0;
3048}
3049
3050void
3051scsi_target_block(struct device *dev)
3052{
3053 if (scsi_is_target_device(dev))
3054 starget_for_each_device(to_scsi_target(dev), NULL,
3055 device_block);
3056 else
3057 device_for_each_child(dev, NULL, target_block);
3058}
3059EXPORT_SYMBOL_GPL(scsi_target_block);
3060
3061static void
3062device_unblock(struct scsi_device *sdev, void *data)
3063{
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003064 scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003065}
3066
3067static int
3068target_unblock(struct device *dev, void *data)
3069{
3070 if (scsi_is_target_device(dev))
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003071 starget_for_each_device(to_scsi_target(dev), data,
Linus Torvalds1da177e2005-04-16 15:20:36 -07003072 device_unblock);
3073 return 0;
3074}
3075
3076void
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003077scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003078{
3079 if (scsi_is_target_device(dev))
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003080 starget_for_each_device(to_scsi_target(dev), &new_state,
Linus Torvalds1da177e2005-04-16 15:20:36 -07003081 device_unblock);
3082 else
Mike Christie5d9fb5c2012-05-17 23:56:57 -05003083 device_for_each_child(dev, &new_state, target_unblock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003084}
3085EXPORT_SYMBOL_GPL(scsi_target_unblock);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003086
3087/**
3088 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
Rob Landleyeb448202007-11-03 13:30:39 -05003089 * @sgl: scatter-gather list
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003090 * @sg_count: number of segments in sg
3091 * @offset: offset in bytes into sg, on return offset into the mapped area
3092 * @len: bytes to map, on return number of bytes mapped
3093 *
3094 * Returns virtual address of the start of the mapped page
3095 */
Jens Axboec6132da2007-10-16 11:08:49 +02003096void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003097 size_t *offset, size_t *len)
3098{
3099 int i;
3100 size_t sg_len = 0, len_complete = 0;
Jens Axboec6132da2007-10-16 11:08:49 +02003101 struct scatterlist *sg;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003102 struct page *page;
3103
Andrew Morton22cfefb2007-02-05 16:39:03 -08003104 WARN_ON(!irqs_disabled());
3105
Jens Axboec6132da2007-10-16 11:08:49 +02003106 for_each_sg(sgl, sg, sg_count, i) {
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003107 len_complete = sg_len; /* Complete sg-entries */
Jens Axboec6132da2007-10-16 11:08:49 +02003108 sg_len += sg->length;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003109 if (sg_len > *offset)
3110 break;
3111 }
3112
3113 if (unlikely(i == sg_count)) {
Andrew Morton169e1a22006-04-18 21:09:08 -07003114 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3115 "elements %d\n",
Harvey Harrisoncadbd4a2008-07-03 23:47:27 -07003116 __func__, sg_len, *offset, sg_count);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003117 WARN_ON(1);
3118 return NULL;
3119 }
3120
3121 /* Offset starting from the beginning of first page in this sg-entry */
Jens Axboec6132da2007-10-16 11:08:49 +02003122 *offset = *offset - len_complete + sg->offset;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003123
3124 /* Assumption: contiguous pages can be accessed as "page + i" */
Jens Axboe45711f12007-10-22 21:19:53 +02003125 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003126 *offset &= ~PAGE_MASK;
3127
3128 /* Bytes in this sg-entry from *offset to the end of the page */
3129 sg_len = PAGE_SIZE - *offset;
3130 if (*len > sg_len)
3131 *len = sg_len;
3132
Cong Wang77dfce02011-11-25 23:14:23 +08003133 return kmap_atomic(page);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003134}
3135EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3136
3137/**
Rob Landleyeb448202007-11-03 13:30:39 -05003138 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003139 * @virt: virtual address to be unmapped
3140 */
3141void scsi_kunmap_atomic_sg(void *virt)
3142{
Cong Wang77dfce02011-11-25 23:14:23 +08003143 kunmap_atomic(virt);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02003144}
3145EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
Aaron Lu6f4c8272013-01-23 15:09:32 +08003146
3147void sdev_disable_disk_events(struct scsi_device *sdev)
3148{
3149 atomic_inc(&sdev->disk_events_disable_depth);
3150}
3151EXPORT_SYMBOL(sdev_disable_disk_events);
3152
3153void sdev_enable_disk_events(struct scsi_device *sdev)
3154{
3155 if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3156 return;
3157 atomic_dec(&sdev->disk_events_disable_depth);
3158}
3159EXPORT_SYMBOL(sdev_enable_disk_events);