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scst_tg: Introduce scst_dg_mutex

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Make target group locking more fine grained by protecting
target group related data structures via scst_dg_mutex. This
patch fixes a rare deadlock between VPD inquiry and LUN removal.
See also patch "scst: Rework sess_tgt_dev_list locking" (commit
ID 5af7d9277d).

INFO: task scst_uid:12943 blocked for more than 120 seconds.
Call Trace:
[<ffffffff814f9297>] schedule+0x37/0x90
[<ffffffff814fe2fc>] schedule_timeout+0x20c/0x370
[<ffffffff814fa8f7>] wait_for_completion+0xf7/0x130
[<ffffffff81083dc4>] kthread_stop+0x84/0x470
[<ffffffffa04286b8>] scst_del_threads+0xc8/0x250 [scst]
[<ffffffffa0457505>] scst_tgt_dev_stop_threads+0x185/0x1a0 [scst]
[<ffffffffa045e913>] scst_free_tgt_dev+0x103/0x280 [scst]
[<ffffffffa045fb6d>] scst_acg_del_lun+0xcd/0x270 [scst]
[<ffffffffa046fc03>] __scst_process_luns_mgmt_store+0x653/0x6b0 [scst]
[<ffffffffa046fc87>] scst_luns_mgmt_store_work_fn+0x27/0x30 [scst]
[<ffffffffa046b00d>] scst_process_sysfs_works+0xed/0x1f0 [scst]
[<ffffffffa046e4bd>] sysfs_work_thread_fn+0x13d/0x2e0 [scst]
[<ffffffff8108370a>] kthread+0x10a/0x120
[<ffffffff815001a2>] ret_from_fork+0x42/0x70
1 lock held by scst_uid/12943:
  (&scst_mutex){+.+.+.}, at: [<ffffffffa045fb4b>] scst_acg_del_lun+0xab/0x270 [scst]
INFO: task diskf00_0:19854 blocked for more than 120 seconds.
Call Trace:
[<ffffffff814f9297>] schedule+0x37/0x90
[<ffffffff814f9738>] schedule_preempt_disabled+0x18/0x30
[<ffffffff814fb1ce>] mutex_lock_nested+0x16e/0x450
[<ffffffffa0483e6f>] scst_impl_alua_configured+0x1f/0x50 [scst]
[<ffffffffa0504878>] vdisk_inq+0x68/0x2c0 [scst_vdisk]
[<ffffffffa050b05e>] vdisk_exec_inquiry+0x31e/0x440 [scst_vdisk]
[<ffffffffa0502bf6>] vdev_do_job+0x1b6/0x3c0 [scst_vdisk]
[<ffffffffa05030a9>] vdisk_exec+0x29/0x90 [scst_vdisk]
[<ffffffffa0431eb1>] scst_do_real_exec+0xa1/0x450 [scst]
[<ffffffffa043230d>] scst_exec_check_blocking+0xad/0x2b0 [scst]
[<ffffffffa043251e>] scst_exec_check_sn+0xe/0x10 [scst]
[<ffffffffa0439e75>] scst_process_active_cmd+0x3f5/0x7e0 [scst]
[<ffffffffa043b7eb>] scst_do_job_active+0xeb/0x180 [scst]
[<ffffffffa043b9bc>] scst_cmd_thread+0x13c/0x2c0 [scst]
[<ffffffff8108370a>] kthread+0x10a/0x120
[<ffffffff815001a2>] ret_from_fork+0x42/0x70
1 lock held by diskf00_0/19854:
  (&scst_mutex){+.+.+.}, at: [<ffffffffa0483e6f>] scst_impl_alua_configured+0x1f/0x50 [scst]

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
This commit is contained in:
Bart Van Assche
2015-05-05 09:35:19 +02:00
parent b71ab710d8
commit eac3a61c3c
1 changed files with 83 additions and 61 deletions
Download Patch File Download Diff File Expand all files Collapse all files

144
scst/src/scst_tg.c
View File

@@ -38,6 +38,11 @@ static const struct alua_state_and_name scst_tg_state_names[] = {
{ SCST_TG_STATE_TRANSITIONING, "transitioning" },
};
/*
* Protects scst_dev_group_list and also dev_list and tg_list in struct
* scst_dev_group.
*/
static DEFINE_MUTEX(scst_dg_mutex);
static LIST_HEAD(scst_dev_group_list);
#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 31) || \
@@ -77,7 +82,7 @@ static struct scst_device *__lookup_dev(const char *name)
{
struct scst_device *dev;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(dev, &scst_dev_list, dev_list_entry)
if (strcmp(dev->virt_name, name) == 0)
@@ -109,7 +114,7 @@ static struct scst_tg_tgt *__lookup_dg_tgt(struct scst_dev_group *dg,
struct scst_target_group *tg;
struct scst_tg_tgt *tg_tgt;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
BUG_ON(!dg);
BUG_ON(!tgt_name);
@@ -127,7 +132,7 @@ __lookup_tg_by_name(struct scst_dev_group *dg, const char *name)
{
struct scst_target_group *tg;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(tg, &dg->tg_list, entry)
if (strcmp(tg->name, name) == 0)
@@ -143,7 +148,7 @@ __lookup_tg_by_tgt(struct scst_dev_group *dg, const struct scst_tgt *tgt)
struct scst_target_group *tg;
struct scst_tg_tgt *tg_tgt;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(tg, &dg->tg_list, entry)
list_for_each_entry(tg_tgt, &tg->tgt_list, entry)
@@ -159,7 +164,7 @@ static struct scst_dg_dev *__lookup_dg_dev_by_dev(struct scst_dev_group *dg,
{
struct scst_dg_dev *dgd;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(dgd, &dg->dev_list, entry)
if (dgd->dev == dev)
@@ -174,7 +179,7 @@ static struct scst_dg_dev *__lookup_dg_dev_by_name(struct scst_dev_group *dg,
{
struct scst_dg_dev *dgd;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(dgd, &dg->dev_list, entry)
if (strcmp(dgd->dev->virt_name, name) == 0)
@@ -189,7 +194,7 @@ static struct scst_dg_dev *__global_lookup_dg_dev_by_name(const char *name)
struct scst_dev_group *dg;
struct scst_dg_dev *dgd;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(dg, &scst_dev_group_list, entry) {
dgd = __lookup_dg_dev_by_name(dg, name);
@@ -204,7 +209,7 @@ static struct scst_dev_group *__lookup_dg_by_name(const char *name)
{
struct scst_dev_group *dg;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(dg, &scst_dev_group_list, entry)
if (strcmp(dg->name, name) == 0)
@@ -218,7 +223,7 @@ static struct scst_dev_group *__lookup_dg_by_dev(struct scst_device *dev)
{
struct scst_dev_group *dg;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(dg, &scst_dev_group_list, entry)
if (__lookup_dg_dev_by_dev(dg, dev))
@@ -335,7 +340,10 @@ static void scst_check_alua_invariant(void)
struct scst_target_group *tg;
enum scst_tg_state expected_state;
lockdep_assert_held(&scst_mutex);
#if 0
lockdep_assert_held(&scst_mutex); /* scst_dev_list, dev_tgt_dev_list */
#endif
lockdep_assert_held(&scst_dg_mutex);
if (!alua_invariant_check)
return;
@@ -370,7 +378,7 @@ static void scst_check_alua_invariant(void)
static void scst_update_tgt_dev_alua_filter(struct scst_tgt_dev *tgt_dev,
enum scst_tg_state state)
{
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
tgt_dev->alua_filter = scst_alua_filter[state];
}
@@ -380,7 +388,7 @@ static void scst_tg_change_tgt_dev_state(struct scst_tgt_dev *tgt_dev,
enum scst_tg_state state,
bool gen_ua)
{
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
TRACE_MGMT_DBG("ALUA state of tgt_dev %p has changed", tgt_dev);
scst_update_tgt_dev_alua_filter(tgt_dev, state);
@@ -395,8 +403,7 @@ void scst_tg_init_tgt_dev(struct scst_tgt_dev *tgt_dev)
struct scst_dev_group *dg;
struct scst_target_group *tg;
lockdep_assert_held(&scst_mutex);
mutex_lock(&scst_dg_mutex);
dg = __lookup_dg_by_dev(tgt_dev->dev);
if (dg) {
tg = __lookup_tg_by_tgt(dg, tgt_dev->acg_dev->acg->tgt);
@@ -405,6 +412,7 @@ void scst_tg_init_tgt_dev(struct scst_tgt_dev *tgt_dev)
scst_check_alua_invariant();
}
}
mutex_unlock(&scst_dg_mutex);
}
/*
@@ -417,7 +425,7 @@ static void scst_update_tgt_alua_filter(struct scst_target_group *tg,
struct scst_dg_dev *dgd;
struct scst_tgt_dev *tgt_dev;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(dgd, &tg->dg->dev_list, entry) {
list_for_each_entry(tgt_dev, &dgd->dev->dev_tgt_dev_list,
@@ -441,7 +449,7 @@ static void scst_reset_tgt_alua_filter(struct scst_target_group *tg,
struct scst_dg_dev *dgd;
struct scst_tgt_dev *tgt_dev;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(dgd, &tg->dg->dev_list, entry) {
list_for_each_entry(tgt_dev, &dgd->dev->dev_tgt_dev_list,
@@ -485,23 +493,33 @@ int scst_tg_tgt_add(struct scst_target_group *tg, const char *name)
res = mutex_lock_interruptible(&scst_mutex);
if (res)
goto out_put;
res = mutex_lock_interruptible(&scst_dg_mutex);
if (res)
goto out_unlock_scst;
res = -EEXIST;
tgt = __lookup_tgt(name);
if (__lookup_dg_tgt(tg->dg, name))
goto out_unlock;
goto out_unlock_dg;
tg_tgt->tgt = tgt;
res = scst_tg_tgt_sysfs_add(tg, tg_tgt);
if (res)
goto out_unlock;
goto out_unlock_dg;
list_add_tail(&tg_tgt->entry, &tg->tgt_list);
scst_update_tgt_alua_filter(tg, tgt);
res = 0;
mutex_unlock(&scst_dg_mutex);
mutex_unlock(&scst_mutex);
out:
TRACE_EXIT_RES(res);
return res;
out_unlock:
out_unlock_dg:
mutex_unlock(&scst_dg_mutex);
out_unlock_scst:
mutex_unlock(&scst_mutex);
out_put:
kobject_put(&tg_tgt->kobj);
goto out;
@@ -529,7 +547,7 @@ int scst_tg_tgt_remove_by_name(struct scst_target_group *tg, const char *name)
TRACE_ENTRY();
BUG_ON(!tg);
BUG_ON(!name);
res = mutex_lock_interruptible(&scst_mutex);
res = mutex_lock_interruptible(&scst_dg_mutex);
if (res)
goto out;
res = -EINVAL;
@@ -539,27 +557,26 @@ int scst_tg_tgt_remove_by_name(struct scst_target_group *tg, const char *name)
__scst_tg_tgt_remove(tg, tg_tgt);
res = 0;
out_unlock:
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out:
TRACE_EXIT_RES(res);
return res;
}
/* Caller must hold scst_mutex. Called from the target removal code. */
/* Called from the target removal code. */
void scst_tg_tgt_remove_by_tgt(struct scst_tgt *tgt)
{
struct scst_dev_group *dg;
struct scst_target_group *tg;
struct scst_tg_tgt *t, *t2;
lockdep_assert_held(&scst_mutex);
BUG_ON(!tgt);
mutex_lock(&scst_dg_mutex);
list_for_each_entry(dg, &scst_dev_group_list, entry)
list_for_each_entry(tg, &dg->tg_list, entry)
list_for_each_entry_safe(t, t2, &tg->tgt_list, entry)
if (t->tgt == tgt)
__scst_tg_tgt_remove(tg, t);
mutex_unlock(&scst_dg_mutex);
}
/*
@@ -608,7 +625,7 @@ int scst_tg_add(struct scst_dev_group *dg, const char *name)
tg->state = SCST_TG_STATE_OPTIMIZED;
INIT_LIST_HEAD(&tg->tgt_list);
res = mutex_lock_interruptible(&scst_mutex);
res = mutex_lock_interruptible(&scst_dg_mutex);
if (res)
goto out_put;
res = -EEXIST;
@@ -618,14 +635,14 @@ int scst_tg_add(struct scst_dev_group *dg, const char *name)
if (res)
goto out_unlock;
list_add_tail(&tg->entry, &dg->tg_list);
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out:
TRACE_EXIT_RES(res);
return res;
out_unlock:
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out_put:
kobject_put(&tg->kobj);
goto out;
@@ -658,7 +675,7 @@ int scst_tg_remove_by_name(struct scst_dev_group *dg, const char *name)
struct scst_target_group *tg;
int res;
res = mutex_lock_interruptible(&scst_mutex);
res = mutex_lock_interruptible(&scst_dg_mutex);
if (res)
goto out;
res = -EINVAL;
@@ -668,7 +685,7 @@ int scst_tg_remove_by_name(struct scst_dev_group *dg, const char *name)
__scst_tg_remove(dg, tg);
res = 0;
out_unlock:
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out:
return res;
}
@@ -689,7 +706,7 @@ static void __scst_tg_set_state(struct scst_target_group *tg,
struct scst_tgt *tgt;
sBUG_ON(state >= ARRAY_SIZE(scst_alua_filter));
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
if (tg->state == state)
return;
@@ -725,13 +742,13 @@ int scst_tg_set_state(struct scst_target_group *tg, enum scst_tg_state state)
if (state >= ARRAY_SIZE(scst_alua_filter))
goto out;
res = mutex_lock_interruptible(&scst_mutex);
res = mutex_lock_interruptible(&scst_dg_mutex);
if (res)
goto out;
__scst_tg_set_state(tg, state, NULL);
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out:
return res;
}
@@ -753,7 +770,7 @@ static void __scst_gen_alua_state_changed_ua(struct scst_target_group *tg)
struct scst_tg_tgt *tg_tgt;
struct scst_tgt *tgt;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(dg_dev, &tg->dg->dev_list, entry) {
dev = dg_dev->dev;
@@ -776,7 +793,7 @@ static void __scst_tg_set_preferred(struct scst_target_group *tg,
{
bool prev_preferred;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
if (tg->preferred == preferred)
return;
@@ -796,11 +813,11 @@ int scst_tg_set_preferred(struct scst_target_group *tg,
{
int res;
res = mutex_lock_interruptible(&scst_mutex);
res = mutex_lock_interruptible(&scst_dg_mutex);
if (res)
goto out;
__scst_tg_set_preferred(tg, preferred);
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out:
return res;
}
@@ -819,7 +836,7 @@ static void scst_update_dev_alua_filter(struct scst_dev_group *dg,
struct scst_tgt_dev *tgt_dev;
struct scst_target_group *tg;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(tgt_dev, &dev->dev_tgt_dev_list,
dev_tgt_dev_list_entry) {
@@ -839,7 +856,7 @@ static void scst_reset_dev_alua_filter(struct scst_device *dev)
{
struct scst_tgt_dev *tgt_dev;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_for_each_entry(tgt_dev, &dev->dev_tgt_dev_list,
dev_tgt_dev_list_entry)
@@ -866,7 +883,7 @@ int scst_dg_dev_add(struct scst_dev_group *dg, const char *name)
if (!dgdev)
goto out;
res = mutex_lock_interruptible(&scst_mutex);
res = mutex_lock_interruptible(&scst_dg_mutex);
if (res)
goto out_free;
res = -EEXIST;
@@ -882,13 +899,13 @@ int scst_dg_dev_add(struct scst_dev_group *dg, const char *name)
goto out_unlock;
list_add_tail(&dgdev->entry, &dg->dev_list);
scst_update_dev_alua_filter(dg, dev);
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out:
return res;
out_unlock:
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out_free:
kfree(dgdev);
goto out;
@@ -911,7 +928,7 @@ int scst_dg_dev_remove_by_name(struct scst_dev_group *dg, const char *name)
struct scst_dg_dev *dgdev;
int res;
res = mutex_lock_interruptible(&scst_mutex);
res = mutex_lock_interruptible(&scst_dg_mutex);
if (res)
goto out;
res = -EINVAL;
@@ -921,12 +938,12 @@ int scst_dg_dev_remove_by_name(struct scst_dev_group *dg, const char *name)
__scst_dg_dev_remove(dg, dgdev);
res = 0;
out_unlock:
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out:
return res;
}
/* Caller must hold scst_mutex. Called from the device removal code. */
/* Called from the device removal code. */
int scst_dg_dev_remove_by_dev(struct scst_device *dev)
{
struct scst_dev_group *dg;
@@ -934,6 +951,8 @@ int scst_dg_dev_remove_by_dev(struct scst_device *dev)
int res;
res = -EINVAL;
mutex_lock(&scst_dg_mutex);
dg = __lookup_dg_by_dev(dev);
if (!dg)
goto out;
@@ -941,7 +960,10 @@ int scst_dg_dev_remove_by_dev(struct scst_device *dev)
BUG_ON(!dgdev);
__scst_dg_dev_remove(dg, dgdev);
res = 0;
out:
mutex_unlock(&scst_dg_mutex);
return res;
}
@@ -989,7 +1011,7 @@ int scst_dg_add(struct kobject *parent, const char *name)
if (!dg->name)
goto out_put;
res = mutex_lock_interruptible(&scst_mutex);
res = mutex_lock_interruptible(&scst_dg_mutex);
if (res)
goto out_put;
res = -EEXIST;
@@ -1002,13 +1024,13 @@ int scst_dg_add(struct kobject *parent, const char *name)
if (res)
goto out_unlock;
list_add_tail(&dg->entry, &scst_dev_group_list);
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out:
TRACE_EXIT_RES(res);
return res;
out_unlock:
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out_put:
kobject_put(&dg->kobj);
goto out;
@@ -1019,7 +1041,7 @@ static void __scst_dg_remove(struct scst_dev_group *dg)
struct scst_dg_dev *dgdev;
struct scst_target_group *tg;
lockdep_assert_held(&scst_mutex);
lockdep_assert_held(&scst_dg_mutex);
list_del(&dg->entry);
scst_dg_sysfs_del(dg);
@@ -1043,7 +1065,7 @@ int scst_dg_remove(const char *name)
struct scst_dev_group *dg;
int res;
res = mutex_lock_interruptible(&scst_mutex);
res = mutex_lock_interruptible(&scst_dg_mutex);
if (res)
goto out;
res = -EINVAL;
@@ -1053,7 +1075,7 @@ int scst_dg_remove(const char *name)
__scst_dg_remove(dg);
res = 0;
out_unlock:
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out:
return res;
}
@@ -1072,7 +1094,7 @@ struct scst_dev_group *scst_lookup_dg_by_kobj(struct kobject *kobj)
struct scst_dev_group *dg;
dg = NULL;
res = mutex_lock_interruptible(&scst_mutex);
res = mutex_lock_interruptible(&scst_dg_mutex);
if (res)
goto out;
list_for_each_entry(dg, &scst_dev_group_list, entry)
@@ -1080,7 +1102,7 @@ struct scst_dev_group *scst_lookup_dg_by_kobj(struct kobject *kobj)
goto out_unlock;
dg = NULL;
out_unlock:
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out:
return dg;
}
@@ -1098,13 +1120,13 @@ void scst_tg_cleanup(void)
{
struct scst_dev_group *tg;
mutex_lock(&scst_mutex);
mutex_lock(&scst_dg_mutex);
while (!list_empty(&scst_dev_group_list)) {
tg = list_first_entry(&scst_dev_group_list,
struct scst_dev_group, entry);
__scst_dg_remove(tg);
}
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
}
/*
@@ -1126,7 +1148,7 @@ uint16_t scst_lookup_tg_id(struct scst_device *dev, struct scst_tgt *tgt)
uint16_t tg_id = 0;
TRACE_ENTRY();
mutex_lock(&scst_mutex);
mutex_lock(&scst_dg_mutex);
dg = __lookup_dg_by_dev(dev);
if (!dg)
goto out_unlock;
@@ -1137,7 +1159,7 @@ uint16_t scst_lookup_tg_id(struct scst_device *dev, struct scst_tgt *tgt)
BUG_ON(!tg);
tg_id = tg->group_id;
out_unlock:
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
TRACE_EXIT_RES(tg_id);
return tg_id;
@@ -1152,9 +1174,9 @@ bool scst_impl_alua_configured(struct scst_device *dev)
{
struct scst_dev_group *dg;
mutex_lock(&scst_mutex);
mutex_lock(&scst_dg_mutex);
dg = __lookup_dg_by_dev(dev);
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
return dg != NULL;
}
@@ -1200,7 +1222,7 @@ int scst_tg_get_group_info(void **buf, uint32_t *length,
*length = 4;
mutex_lock(&scst_mutex);
mutex_lock(&scst_dg_mutex);
dg = __lookup_dg_by_dev(dev);
if (dg) {
@@ -1267,7 +1289,7 @@ done:
res = 0;
out_unlock:
mutex_unlock(&scst_mutex);
mutex_unlock(&scst_dg_mutex);
out:
TRACE_EXIT_RES(res);
return res;