aboutsummaryrefslogtreecommitdiff
path: root/drivers/vhost
diff options
context:
space:
mode:
authorNicholas Bellinger <nab@linux-iscsi.org>2012-07-30 13:30:00 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2012-08-16 17:33:40 -0700
commit101998f6fcd680ed12d85633b81504feb1cb0667 (patch)
treee2d323c4e7a2f09cadd675d59e003330130c6563 /drivers/vhost
parentf0e0e9bba5eed2086f6001be14f21566a49bed10 (diff)
downloadlinux-linaro-stable-101998f6fcd680ed12d85633b81504feb1cb0667.tar.gz
tcm_vhost: Post-merge review changes requested by MST
This patch contains the post RFC-v5 (post-merge) changes, this includes: - Add locking comment - Move vhost_scsi_complete_cmd ahead of TFO callbacks in order to drop forward declarations - Drop extra '!= NULL' usage in vhost_scsi_complete_cmd_work() - Change vhost_scsi_*_handle_kick() to use pr_debug - Fix possible race in vhost_scsi_set_endpoint() for vs->vs_tpg checking + assignment. - Convert tv_tpg->tpg_vhost_count + ->tv_tpg_port_count from atomic_t -> int, and make sure reference is protected by ->tv_tpg_mutex. - Drop unnecessary vhost_scsi->vhost_ref_cnt - Add 'err:' label for exception path in vhost_scsi_clear_endpoint() - Add enum for VQ numbers, add usage in vhost_scsi_open() - Add vhost_scsi_flush() + vhost_scsi_flush_vq() following drivers/vhost/net.c - Add smp_wmb() + vhost_scsi_flush() call during vhost_scsi_set_features() - Drop unnecessary copy_from_user() usage with GET_ABI_VERSION ioctl - Add missing vhost_scsi_compat_ioctl() caller for vhost_scsi_fops - Fix function parameter definition first line to follow existing vhost code style - Change 'vHost' usage -> 'vhost' in handful of locations - Change -EPERM -> -EBUSY usage for two failures in tcm_vhost_drop_nexus() - Add comment for tcm_vhost_workqueue in tcm_vhost_init() - Make GET_ABI_VERSION return 'int' + add comment in tcm_vhost.h Reported-by: Michael S. Tsirkin <mst@redhat.com> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> Cc: Anthony Liguori <aliguori@us.ibm.com> Cc: Zhi Yong Wu <wuzhy@cn.ibm.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/vhost')
-rw-r--r--drivers/vhost/tcm_vhost.c195
-rw-r--r--drivers/vhost/tcm_vhost.h9
2 files changed, 111 insertions, 93 deletions
diff --git a/drivers/vhost/tcm_vhost.c b/drivers/vhost/tcm_vhost.c
index 481af88a5ff5..74b2edaaf1f6 100644
--- a/drivers/vhost/tcm_vhost.c
+++ b/drivers/vhost/tcm_vhost.c
@@ -53,9 +53,14 @@
#include "vhost.h"
#include "tcm_vhost.h"
+enum {
+ VHOST_SCSI_VQ_CTL = 0,
+ VHOST_SCSI_VQ_EVT = 1,
+ VHOST_SCSI_VQ_IO = 2,
+};
+
struct vhost_scsi {
- atomic_t vhost_ref_cnt;
- struct tcm_vhost_tpg *vs_tpg;
+ struct tcm_vhost_tpg *vs_tpg; /* Protected by vhost_scsi->dev.mutex */
struct vhost_dev dev;
struct vhost_virtqueue vqs[3];
@@ -131,8 +136,7 @@ static u32 tcm_vhost_get_default_depth(struct se_portal_group *se_tpg)
return 1;
}
-static u32 tcm_vhost_get_pr_transport_id(
- struct se_portal_group *se_tpg,
+static u32 tcm_vhost_get_pr_transport_id(struct se_portal_group *se_tpg,
struct se_node_acl *se_nacl,
struct t10_pr_registration *pr_reg,
int *format_code,
@@ -162,8 +166,7 @@ static u32 tcm_vhost_get_pr_transport_id(
format_code, buf);
}
-static u32 tcm_vhost_get_pr_transport_id_len(
- struct se_portal_group *se_tpg,
+static u32 tcm_vhost_get_pr_transport_id_len(struct se_portal_group *se_tpg,
struct se_node_acl *se_nacl,
struct t10_pr_registration *pr_reg,
int *format_code)
@@ -192,8 +195,7 @@ static u32 tcm_vhost_get_pr_transport_id_len(
format_code);
}
-static char *tcm_vhost_parse_pr_out_transport_id(
- struct se_portal_group *se_tpg,
+static char *tcm_vhost_parse_pr_out_transport_id(struct se_portal_group *se_tpg,
const char *buf,
u32 *out_tid_len,
char **port_nexus_ptr)
@@ -236,8 +238,7 @@ static struct se_node_acl *tcm_vhost_alloc_fabric_acl(
return &nacl->se_node_acl;
}
-static void tcm_vhost_release_fabric_acl(
- struct se_portal_group *se_tpg,
+static void tcm_vhost_release_fabric_acl(struct se_portal_group *se_tpg,
struct se_node_acl *se_nacl)
{
struct tcm_vhost_nacl *nacl = container_of(se_nacl,
@@ -297,7 +298,16 @@ static int tcm_vhost_get_cmd_state(struct se_cmd *se_cmd)
return 0;
}
-static void vhost_scsi_complete_cmd(struct tcm_vhost_cmd *);
+static void vhost_scsi_complete_cmd(struct tcm_vhost_cmd *tv_cmd)
+{
+ struct vhost_scsi *vs = tv_cmd->tvc_vhost;
+
+ spin_lock_bh(&vs->vs_completion_lock);
+ list_add_tail(&tv_cmd->tvc_completion_list, &vs->vs_completion_list);
+ spin_unlock_bh(&vs->vs_completion_lock);
+
+ vhost_work_queue(&vs->dev, &vs->vs_completion_work);
+}
static int tcm_vhost_queue_data_in(struct se_cmd *se_cmd)
{
@@ -381,7 +391,7 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
vs_completion_work);
struct tcm_vhost_cmd *tv_cmd;
- while ((tv_cmd = vhost_scsi_get_cmd_from_completion(vs)) != NULL) {
+ while ((tv_cmd = vhost_scsi_get_cmd_from_completion(vs))) {
struct virtio_scsi_cmd_resp v_rsp;
struct se_cmd *se_cmd = &tv_cmd->tvc_se_cmd;
int ret;
@@ -408,19 +418,6 @@ static void vhost_scsi_complete_cmd_work(struct vhost_work *work)
vhost_signal(&vs->dev, &vs->vqs[2]);
}
-static void vhost_scsi_complete_cmd(struct tcm_vhost_cmd *tv_cmd)
-{
- struct vhost_scsi *vs = tv_cmd->tvc_vhost;
-
- pr_debug("%s tv_cmd %p\n", __func__, tv_cmd);
-
- spin_lock_bh(&vs->vs_completion_lock);
- list_add_tail(&tv_cmd->tvc_completion_list, &vs->vs_completion_list);
- spin_unlock_bh(&vs->vs_completion_lock);
-
- vhost_work_queue(&vs->dev, &vs->vs_completion_work);
-}
-
static struct tcm_vhost_cmd *vhost_scsi_allocate_cmd(
struct tcm_vhost_tpg *tv_tpg,
struct virtio_scsi_cmd_req *v_req,
@@ -787,12 +784,12 @@ static void vhost_scsi_handle_vq(struct vhost_scsi *vs)
static void vhost_scsi_ctl_handle_kick(struct vhost_work *work)
{
- pr_err("%s: The handling func for control queue.\n", __func__);
+ pr_debug("%s: The handling func for control queue.\n", __func__);
}
static void vhost_scsi_evt_handle_kick(struct vhost_work *work)
{
- pr_err("%s: The handling func for event queue.\n", __func__);
+ pr_debug("%s: The handling func for event queue.\n", __func__);
}
static void vhost_scsi_handle_kick(struct vhost_work *work)
@@ -825,11 +822,6 @@ static int vhost_scsi_set_endpoint(
return -EFAULT;
}
}
-
- if (vs->vs_tpg) {
- mutex_unlock(&vs->dev.mutex);
- return -EEXIST;
- }
mutex_unlock(&vs->dev.mutex);
mutex_lock(&tcm_vhost_mutex);
@@ -839,7 +831,7 @@ static int vhost_scsi_set_endpoint(
mutex_unlock(&tv_tpg->tv_tpg_mutex);
continue;
}
- if (atomic_read(&tv_tpg->tv_tpg_vhost_count)) {
+ if (tv_tpg->tv_tpg_vhost_count != 0) {
mutex_unlock(&tv_tpg->tv_tpg_mutex);
continue;
}
@@ -847,14 +839,20 @@ static int vhost_scsi_set_endpoint(
if (!strcmp(tv_tport->tport_name, t->vhost_wwpn) &&
(tv_tpg->tport_tpgt == t->vhost_tpgt)) {
- atomic_inc(&tv_tpg->tv_tpg_vhost_count);
- smp_mb__after_atomic_inc();
+ tv_tpg->tv_tpg_vhost_count++;
mutex_unlock(&tv_tpg->tv_tpg_mutex);
mutex_unlock(&tcm_vhost_mutex);
mutex_lock(&vs->dev.mutex);
+ if (vs->vs_tpg) {
+ mutex_unlock(&vs->dev.mutex);
+ mutex_lock(&tv_tpg->tv_tpg_mutex);
+ tv_tpg->tv_tpg_vhost_count--;
+ mutex_unlock(&tv_tpg->tv_tpg_mutex);
+ return -EEXIST;
+ }
+
vs->vs_tpg = tv_tpg;
- atomic_inc(&vs->vhost_ref_cnt);
smp_mb__after_atomic_inc();
mutex_unlock(&vs->dev.mutex);
return 0;
@@ -871,38 +869,42 @@ static int vhost_scsi_clear_endpoint(
{
struct tcm_vhost_tport *tv_tport;
struct tcm_vhost_tpg *tv_tpg;
- int index;
+ int index, ret;
mutex_lock(&vs->dev.mutex);
/* Verify that ring has been setup correctly. */
for (index = 0; index < vs->dev.nvqs; ++index) {
if (!vhost_vq_access_ok(&vs->vqs[index])) {
- mutex_unlock(&vs->dev.mutex);
- return -EFAULT;
+ ret = -EFAULT;
+ goto err;
}
}
if (!vs->vs_tpg) {
- mutex_unlock(&vs->dev.mutex);
- return -ENODEV;
+ ret = -ENODEV;
+ goto err;
}
tv_tpg = vs->vs_tpg;
tv_tport = tv_tpg->tport;
if (strcmp(tv_tport->tport_name, t->vhost_wwpn) ||
(tv_tpg->tport_tpgt != t->vhost_tpgt)) {
- mutex_unlock(&vs->dev.mutex);
pr_warn("tv_tport->tport_name: %s, tv_tpg->tport_tpgt: %hu"
" does not match t->vhost_wwpn: %s, t->vhost_tpgt: %hu\n",
tv_tport->tport_name, tv_tpg->tport_tpgt,
t->vhost_wwpn, t->vhost_tpgt);
- return -EINVAL;
+ ret = -EINVAL;
+ goto err;
}
- atomic_dec(&tv_tpg->tv_tpg_vhost_count);
+ tv_tpg->tv_tpg_vhost_count--;
vs->vs_tpg = NULL;
mutex_unlock(&vs->dev.mutex);
return 0;
+
+err:
+ mutex_unlock(&vs->dev.mutex);
+ return ret;
}
static int vhost_scsi_open(struct inode *inode, struct file *f)
@@ -918,9 +920,9 @@ static int vhost_scsi_open(struct inode *inode, struct file *f)
INIT_LIST_HEAD(&s->vs_completion_list);
spin_lock_init(&s->vs_completion_lock);
- s->vqs[0].handle_kick = vhost_scsi_ctl_handle_kick;
- s->vqs[1].handle_kick = vhost_scsi_evt_handle_kick;
- s->vqs[2].handle_kick = vhost_scsi_handle_kick;
+ s->vqs[VHOST_SCSI_VQ_CTL].handle_kick = vhost_scsi_ctl_handle_kick;
+ s->vqs[VHOST_SCSI_VQ_EVT].handle_kick = vhost_scsi_evt_handle_kick;
+ s->vqs[VHOST_SCSI_VQ_IO].handle_kick = vhost_scsi_handle_kick;
r = vhost_dev_init(&s->dev, s->vqs, 3);
if (r < 0) {
kfree(s);
@@ -949,6 +951,18 @@ static int vhost_scsi_release(struct inode *inode, struct file *f)
return 0;
}
+static void vhost_scsi_flush_vq(struct vhost_scsi *vs, int index)
+{
+ vhost_poll_flush(&vs->dev.vqs[index].poll);
+}
+
+static void vhost_scsi_flush(struct vhost_scsi *vs)
+{
+ vhost_scsi_flush_vq(vs, VHOST_SCSI_VQ_CTL);
+ vhost_scsi_flush_vq(vs, VHOST_SCSI_VQ_EVT);
+ vhost_scsi_flush_vq(vs, VHOST_SCSI_VQ_IO);
+}
+
static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features)
{
if (features & ~VHOST_FEATURES)
@@ -961,7 +975,8 @@ static int vhost_scsi_set_features(struct vhost_scsi *vs, u64 features)
return -EFAULT;
}
vs->dev.acked_features = features;
- /* TODO possibly smp_wmb() and flush vqs */
+ smp_wmb();
+ vhost_scsi_flush(vs);
mutex_unlock(&vs->dev.mutex);
return 0;
}
@@ -974,7 +989,7 @@ static long vhost_scsi_ioctl(struct file *f, unsigned int ioctl,
void __user *argp = (void __user *)arg;
u64 __user *featurep = argp;
u64 features;
- int r;
+ int r, abi_version = VHOST_SCSI_ABI_VERSION;
switch (ioctl) {
case VHOST_SCSI_SET_ENDPOINT:
@@ -988,12 +1003,7 @@ static long vhost_scsi_ioctl(struct file *f, unsigned int ioctl,
return vhost_scsi_clear_endpoint(vs, &backend);
case VHOST_SCSI_GET_ABI_VERSION:
- if (copy_from_user(&backend, argp, sizeof backend))
- return -EFAULT;
-
- backend.abi_version = VHOST_SCSI_ABI_VERSION;
-
- if (copy_to_user(argp, &backend, sizeof backend))
+ if (copy_to_user(argp, &abi_version, sizeof abi_version))
return -EFAULT;
return 0;
case VHOST_GET_FEATURES:
@@ -1013,11 +1023,21 @@ static long vhost_scsi_ioctl(struct file *f, unsigned int ioctl,
}
}
+#ifdef CONFIG_COMPAT
+static long vhost_scsi_compat_ioctl(struct file *f, unsigned int ioctl,
+ unsigned long arg)
+{
+ return vhost_scsi_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
+}
+#endif
+
static const struct file_operations vhost_scsi_fops = {
.owner = THIS_MODULE,
.release = vhost_scsi_release,
.unlocked_ioctl = vhost_scsi_ioctl,
- /* TODO compat ioctl? */
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = vhost_scsi_compat_ioctl,
+#endif
.open = vhost_scsi_open,
.llseek = noop_llseek,
};
@@ -1054,28 +1074,28 @@ static char *tcm_vhost_dump_proto_id(struct tcm_vhost_tport *tport)
return "Unknown";
}
-static int tcm_vhost_port_link(
- struct se_portal_group *se_tpg,
+static int tcm_vhost_port_link(struct se_portal_group *se_tpg,
struct se_lun *lun)
{
struct tcm_vhost_tpg *tv_tpg = container_of(se_tpg,
struct tcm_vhost_tpg, se_tpg);
- atomic_inc(&tv_tpg->tv_tpg_port_count);
- smp_mb__after_atomic_inc();
+ mutex_lock(&tv_tpg->tv_tpg_mutex);
+ tv_tpg->tv_tpg_port_count++;
+ mutex_unlock(&tv_tpg->tv_tpg_mutex);
return 0;
}
-static void tcm_vhost_port_unlink(
- struct se_portal_group *se_tpg,
+static void tcm_vhost_port_unlink(struct se_portal_group *se_tpg,
struct se_lun *se_lun)
{
struct tcm_vhost_tpg *tv_tpg = container_of(se_tpg,
struct tcm_vhost_tpg, se_tpg);
- atomic_dec(&tv_tpg->tv_tpg_port_count);
- smp_mb__after_atomic_dec();
+ mutex_lock(&tv_tpg->tv_tpg_mutex);
+ tv_tpg->tv_tpg_port_count--;
+ mutex_unlock(&tv_tpg->tv_tpg_mutex);
}
static struct se_node_acl *tcm_vhost_make_nodeacl(
@@ -1122,8 +1142,7 @@ static void tcm_vhost_drop_nodeacl(struct se_node_acl *se_acl)
kfree(nacl);
}
-static int tcm_vhost_make_nexus(
- struct tcm_vhost_tpg *tv_tpg,
+static int tcm_vhost_make_nexus(struct tcm_vhost_tpg *tv_tpg,
const char *name)
{
struct se_portal_group *se_tpg;
@@ -1168,7 +1187,7 @@ static int tcm_vhost_make_nexus(
return -ENOMEM;
}
/*
- * Now register the TCM vHost virtual I_T Nexus as active with the
+ * Now register the TCM vhost virtual I_T Nexus as active with the
* call to __transport_register_session()
*/
__transport_register_session(se_tpg, tv_nexus->tvn_se_sess->se_node_acl,
@@ -1179,8 +1198,7 @@ static int tcm_vhost_make_nexus(
return 0;
}
-static int tcm_vhost_drop_nexus(
- struct tcm_vhost_tpg *tpg)
+static int tcm_vhost_drop_nexus(struct tcm_vhost_tpg *tpg)
{
struct se_session *se_sess;
struct tcm_vhost_nexus *tv_nexus;
@@ -1198,27 +1216,27 @@ static int tcm_vhost_drop_nexus(
return -ENODEV;
}
- if (atomic_read(&tpg->tv_tpg_port_count)) {
+ if (tpg->tv_tpg_port_count != 0) {
mutex_unlock(&tpg->tv_tpg_mutex);
- pr_err("Unable to remove TCM_vHost I_T Nexus with"
+ pr_err("Unable to remove TCM_vhost I_T Nexus with"
" active TPG port count: %d\n",
- atomic_read(&tpg->tv_tpg_port_count));
- return -EPERM;
+ tpg->tv_tpg_port_count);
+ return -EBUSY;
}
- if (atomic_read(&tpg->tv_tpg_vhost_count)) {
+ if (tpg->tv_tpg_vhost_count != 0) {
mutex_unlock(&tpg->tv_tpg_mutex);
- pr_err("Unable to remove TCM_vHost I_T Nexus with"
+ pr_err("Unable to remove TCM_vhost I_T Nexus with"
" active TPG vhost count: %d\n",
- atomic_read(&tpg->tv_tpg_vhost_count));
- return -EPERM;
+ tpg->tv_tpg_vhost_count);
+ return -EBUSY;
}
- pr_debug("TCM_vHost_ConfigFS: Removing I_T Nexus to emulated"
+ pr_debug("TCM_vhost_ConfigFS: Removing I_T Nexus to emulated"
" %s Initiator Port: %s\n", tcm_vhost_dump_proto_id(tpg->tport),
tv_nexus->tvn_se_sess->se_node_acl->initiatorname);
/*
- * Release the SCSI I_T Nexus to the emulated vHost Target Port
+ * Release the SCSI I_T Nexus to the emulated vhost Target Port
*/
transport_deregister_session(tv_nexus->tvn_se_sess);
tpg->tpg_nexus = NULL;
@@ -1228,8 +1246,7 @@ static int tcm_vhost_drop_nexus(
return 0;
}
-static ssize_t tcm_vhost_tpg_show_nexus(
- struct se_portal_group *se_tpg,
+static ssize_t tcm_vhost_tpg_show_nexus(struct se_portal_group *se_tpg,
char *page)
{
struct tcm_vhost_tpg *tv_tpg = container_of(se_tpg,
@@ -1250,8 +1267,7 @@ static ssize_t tcm_vhost_tpg_show_nexus(
return ret;
}
-static ssize_t tcm_vhost_tpg_store_nexus(
- struct se_portal_group *se_tpg,
+static ssize_t tcm_vhost_tpg_store_nexus(struct se_portal_group *se_tpg,
const char *page,
size_t count)
{
@@ -1336,8 +1352,7 @@ static struct configfs_attribute *tcm_vhost_tpg_attrs[] = {
NULL,
};
-static struct se_portal_group *tcm_vhost_make_tpg(
- struct se_wwn *wwn,
+static struct se_portal_group *tcm_vhost_make_tpg(struct se_wwn *wwn,
struct config_group *group,
const char *name)
{
@@ -1385,7 +1400,7 @@ static void tcm_vhost_drop_tpg(struct se_portal_group *se_tpg)
list_del(&tpg->tv_tpg_list);
mutex_unlock(&tcm_vhost_mutex);
/*
- * Release the virtual I_T Nexus for this vHost TPG
+ * Release the virtual I_T Nexus for this vhost TPG
*/
tcm_vhost_drop_nexus(tpg);
/*
@@ -1395,8 +1410,7 @@ static void tcm_vhost_drop_tpg(struct se_portal_group *se_tpg)
kfree(tpg);
}
-static struct se_wwn *tcm_vhost_make_tport(
- struct target_fabric_configfs *tf,
+static struct se_wwn *tcm_vhost_make_tport(struct target_fabric_configfs *tf,
struct config_group *group,
const char *name)
{
@@ -1592,7 +1606,10 @@ static void tcm_vhost_deregister_configfs(void)
static int __init tcm_vhost_init(void)
{
int ret = -ENOMEM;
-
+ /*
+ * Use our own dedicated workqueue for submitting I/O into
+ * target core to avoid contention within system_wq.
+ */
tcm_vhost_workqueue = alloc_workqueue("tcm_vhost", 0, 0);
if (!tcm_vhost_workqueue)
goto out;
diff --git a/drivers/vhost/tcm_vhost.h b/drivers/vhost/tcm_vhost.h
index c983ed21e413..eff42df14de9 100644
--- a/drivers/vhost/tcm_vhost.h
+++ b/drivers/vhost/tcm_vhost.h
@@ -47,9 +47,9 @@ struct tcm_vhost_tpg {
/* Vhost port target portal group tag for TCM */
u16 tport_tpgt;
/* Used to track number of TPG Port/Lun Links wrt to explict I_T Nexus shutdown */
- atomic_t tv_tpg_port_count;
- /* Used for vhost_scsi device reference to tpg_nexus */
- atomic_t tv_tpg_vhost_count;
+ int tv_tpg_port_count;
+ /* Used for vhost_scsi device reference to tpg_nexus, protected by tv_tpg_mutex */
+ int tv_tpg_vhost_count;
/* list for tcm_vhost_list */
struct list_head tv_tpg_list;
/* Used to protect access for tpg_nexus */
@@ -98,4 +98,5 @@ struct vhost_scsi_target {
/* VHOST_SCSI specific defines */
#define VHOST_SCSI_SET_ENDPOINT _IOW(VHOST_VIRTIO, 0x40, struct vhost_scsi_target)
#define VHOST_SCSI_CLEAR_ENDPOINT _IOW(VHOST_VIRTIO, 0x41, struct vhost_scsi_target)
-#define VHOST_SCSI_GET_ABI_VERSION _IOW(VHOST_VIRTIO, 0x42, struct vhost_scsi_target)
+/* Changing this breaks userspace. */
+#define VHOST_SCSI_GET_ABI_VERSION _IOW(VHOST_VIRTIO, 0x42, int)