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authorTejun Heo <tj@kernel.org>2014-07-23 09:05:27 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-07-31 12:53:49 -0700
commit03cccb9c9ec674407285d3a000b9380c946e21c1 (patch)
tree6a067f18fd0008127d2ad5a7e819216e2d4632de /drivers/ata
parent97a230703c9f6cbed3bdd4d4a627863c14a8a2de (diff)
downloadlinux-linaro-stable-03cccb9c9ec674407285d3a000b9380c946e21c1.tar.gz
libata: introduce ata_host->n_tags to avoid oops on SAS controllers
commit 1a112d10f03e83fb3a2fdc4c9165865dec8a3ca6 upstream. 1871ee134b73 ("libata: support the ata host which implements a queue depth less than 32") directly used ata_port->scsi_host->can_queue from ata_qc_new() to determine the number of tags supported by the host; unfortunately, SAS controllers doing SATA don't initialize ->scsi_host leading to the following oops. BUG: unable to handle kernel NULL pointer dereference at 0000000000000058 IP: [<ffffffff814e0618>] ata_qc_new_init+0x188/0x1b0 PGD 0 Oops: 0002 [#1] SMP Modules linked in: isci libsas scsi_transport_sas mgag200 drm_kms_helper ttm CPU: 1 PID: 518 Comm: udevd Not tainted 3.16.0-rc6+ #62 Hardware name: Intel Corporation S2600CO/S2600CO, BIOS SE5C600.86B.02.02.0002.122320131210 12/23/2013 task: ffff880c1a00b280 ti: ffff88061a000000 task.ti: ffff88061a000000 RIP: 0010:[<ffffffff814e0618>] [<ffffffff814e0618>] ata_qc_new_init+0x188/0x1b0 RSP: 0018:ffff88061a003ae8 EFLAGS: 00010012 RAX: 0000000000000001 RBX: ffff88000241ca80 RCX: 00000000000000fa RDX: 0000000000000020 RSI: 0000000000000020 RDI: ffff8806194aa298 RBP: ffff88061a003ae8 R08: ffff8806194a8000 R09: 0000000000000000 R10: 0000000000000000 R11: ffff88000241ca80 R12: ffff88061ad58200 R13: ffff8806194aa298 R14: ffffffff814e67a0 R15: ffff8806194a8000 FS: 00007f3ad7fe3840(0000) GS:ffff880627620000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000058 CR3: 000000061a118000 CR4: 00000000001407e0 Stack: ffff88061a003b20 ffffffff814e96e1 ffff88000241ca80 ffff88061ad58200 ffff8800b6bf6000 ffff880c1c988000 ffff880619903850 ffff88061a003b68 ffffffffa0056ce1 ffff88061a003b48 0000000013d6e6f8 ffff88000241ca80 Call Trace: [<ffffffff814e96e1>] ata_sas_queuecmd+0xa1/0x430 [<ffffffffa0056ce1>] sas_queuecommand+0x191/0x220 [libsas] [<ffffffff8149afee>] scsi_dispatch_cmd+0x10e/0x300 [<ffffffff814a3bc5>] scsi_request_fn+0x2f5/0x550 [<ffffffff81317613>] __blk_run_queue+0x33/0x40 [<ffffffff8131781a>] queue_unplugged+0x2a/0x90 [<ffffffff8131ceb4>] blk_flush_plug_list+0x1b4/0x210 [<ffffffff8131d274>] blk_finish_plug+0x14/0x50 [<ffffffff8117eaa8>] __do_page_cache_readahead+0x198/0x1f0 [<ffffffff8117ee21>] force_page_cache_readahead+0x31/0x50 [<ffffffff8117ee7e>] page_cache_sync_readahead+0x3e/0x50 [<ffffffff81172ac6>] generic_file_read_iter+0x496/0x5a0 [<ffffffff81219897>] blkdev_read_iter+0x37/0x40 [<ffffffff811e307e>] new_sync_read+0x7e/0xb0 [<ffffffff811e3734>] vfs_read+0x94/0x170 [<ffffffff811e43c6>] SyS_read+0x46/0xb0 [<ffffffff811e33d1>] ? SyS_lseek+0x91/0xb0 [<ffffffff8171ee29>] system_call_fastpath+0x16/0x1b Code: 00 00 00 88 50 29 83 7f 08 01 19 d2 83 e2 f0 83 ea 50 88 50 34 c6 81 1d 02 00 00 40 c6 81 17 02 00 00 00 5d c3 66 0f 1f 44 00 00 <89> 14 25 58 00 00 00 Fix it by introducing ata_host->n_tags which is initialized to ATA_MAX_QUEUE - 1 in ata_host_init() for SAS controllers and set to scsi_host_template->can_queue in ata_host_register() for !SAS ones. As SAS hosts are never registered, this will give them the same ATA_MAX_QUEUE - 1 as before. Note that we can't use scsi_host->can_queue directly for SAS hosts anyway as they can go higher than the libata maximum. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Mike Qiu <qiudayu@linux.vnet.ibm.com> Reported-by: Jesse Brandeburg <jesse.brandeburg@gmail.com> Reported-by: Peter Hurley <peter@hurleysoftware.com> Reported-by: Peter Zijlstra <peterz@infradead.org> Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru> Fixes: 1871ee134b73 ("libata: support the ata host which implements a queue depth less than 32") Cc: Kevin Hao <haokexin@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/ata')
-rw-r--r--drivers/ata/libata-core.c16
1 files changed, 4 insertions, 12 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index d7fb8269cb73..ca7c23d58a03 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -4769,9 +4769,8 @@ void swap_buf_le16(u16 *buf, unsigned int buf_words)
static struct ata_queued_cmd *ata_qc_new(struct ata_port *ap)
{
struct ata_queued_cmd *qc = NULL;
- unsigned int i, tag, max_queue;
-
- max_queue = ap->scsi_host->can_queue;
+ unsigned int max_queue = ap->host->n_tags;
+ unsigned int i, tag;
/* no command while frozen */
if (unlikely(ap->pflags & ATA_PFLAG_FROZEN))
@@ -6079,6 +6078,7 @@ void ata_host_init(struct ata_host *host, struct device *dev,
{
spin_lock_init(&host->lock);
mutex_init(&host->eh_mutex);
+ host->n_tags = ATA_MAX_QUEUE - 1;
host->dev = dev;
host->ops = ops;
}
@@ -6160,15 +6160,7 @@ int ata_host_register(struct ata_host *host, struct scsi_host_template *sht)
{
int i, rc;
- /*
- * The max queue supported by hardware must not be greater than
- * ATA_MAX_QUEUE.
- */
- if (sht->can_queue > ATA_MAX_QUEUE) {
- dev_err(host->dev, "BUG: the hardware max queue is too large\n");
- WARN_ON(1);
- return -EINVAL;
- }
+ host->n_tags = clamp(sht->can_queue, 1, ATA_MAX_QUEUE - 1);
/* host must have been started */
if (!(host->flags & ATA_HOST_STARTED)) {