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target: Fix remote-port TMR ABORT + se_cmd fabric stop

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To address the bug where fabric driver level shutdown
of se_cmd occurs at the same time when TMR CMD_T_ABORTED
is happening resulting in a -1 ->cmd_kref, this patch
adds a CMD_T_FABRIC_STOP bit that is used to determine
when TMR + driver I_T nexus shutdown is happening
concurrently.

It changes target_sess_cmd_list_set_waiting() to obtain
se_cmd->cmd_kref + set CMD_T_FABRIC_STOP, and drop local
reference in target_wait_for_sess_cmds() and invoke extra
target_put_sess_cmd() during Task Aborted Status (TAS)
when necessary.

Also, it adds a new target_wait_free_cmd() wrapper around
transport_wait_for_tasks() for the special case within
transport_generic_free_cmd() to set CMD_T_FABRIC_STOP,
and is now aware of CMD_T_ABORTED + CMD_T_TAS status
bits to know when an extra transport_put_cmd() during
TAS is required.

Note transport_generic_free_cmd() is expected to block on
cmd->cmd_wait_comp in order to follow what iscsi-target
expects during iscsi_conn context se_cmd shutdown.

Cc: Quinn Tran <quinn.tran@qlogic.com>
Cc: Himanshu Madhani <himanshu.madhani@qlogic.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>
This commit is contained in:
Nicholas Bellinger 2016-01-19 15:23:02 -08:00
parent ebde1ca5a9
commit 0f4a943168
3 changed files with 157 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

54
drivers/target/target_core_tmr.c
View File

@ -75,16 +75,18 @@ void core_tmr_release_req(struct se_tmr_req *tmr)
kfree(tmr);
}
static void core_tmr_handle_tas_abort(
struct se_session *tmr_sess,
struct se_cmd *cmd,
int tas)
static void core_tmr_handle_tas_abort(struct se_cmd *cmd, int tas)
{
bool remove = true;
unsigned long flags;
bool remove = true, send_tas;
/*
* TASK ABORTED status (TAS) bit support
*/
if (tmr_sess && tmr_sess != cmd->se_sess && tas) {
spin_lock_irqsave(&cmd->t_state_lock, flags);
send_tas = (cmd->transport_state & CMD_T_TAS);
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
if (send_tas) {
remove = false;
transport_send_task_abort(cmd);
}
@ -107,7 +109,8 @@ static int target_check_cdb_and_preempt(struct list_head *list,
return 1;
}
static bool __target_check_io_state(struct se_cmd *se_cmd)
static bool __target_check_io_state(struct se_cmd *se_cmd,
struct se_session *tmr_sess, int tas)
{
struct se_session *sess = se_cmd->se_sess;
@ -115,21 +118,32 @@ static bool __target_check_io_state(struct se_cmd *se_cmd)
WARN_ON_ONCE(!irqs_disabled());
/*
* If command already reached CMD_T_COMPLETE state within
* target_complete_cmd(), this se_cmd has been passed to
* fabric driver and will not be aborted.
* target_complete_cmd() or CMD_T_FABRIC_STOP due to shutdown,
* this se_cmd has been passed to fabric driver and will
* not be aborted.
*
* Otherwise, obtain a local se_cmd->cmd_kref now for TMR
* ABORT_TASK + LUN_RESET for CMD_T_ABORTED processing as
* long as se_cmd->cmd_kref is still active unless zero.
*/
spin_lock(&se_cmd->t_state_lock);
if (se_cmd->transport_state & CMD_T_COMPLETE) {
pr_debug("Attempted to abort io tag: %llu already complete,"
if (se_cmd->transport_state & (CMD_T_COMPLETE | CMD_T_FABRIC_STOP)) {
pr_debug("Attempted to abort io tag: %llu already complete or"
" fabric stop, skipping\n", se_cmd->tag);
spin_unlock(&se_cmd->t_state_lock);
return false;
}
if (sess->sess_tearing_down || se_cmd->cmd_wait_set) {
pr_debug("Attempted to abort io tag: %llu already shutdown,"
" skipping\n", se_cmd->tag);
spin_unlock(&se_cmd->t_state_lock);
return false;
}
se_cmd->transport_state |= CMD_T_ABORTED;
if ((tmr_sess != se_cmd->se_sess) && tas)
se_cmd->transport_state |= CMD_T_TAS;
spin_unlock(&se_cmd->t_state_lock);
return kref_get_unless_zero(&se_cmd->cmd_kref);
@ -161,7 +175,7 @@ void core_tmr_abort_task(
printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",
se_cmd->se_tfo->get_fabric_name(), ref_tag);
if (!__target_check_io_state(se_cmd)) {
if (!__target_check_io_state(se_cmd, se_sess, 0)) {
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
target_put_sess_cmd(se_cmd);
goto out;
@ -230,7 +244,8 @@ static void core_tmr_drain_tmr_list(
spin_lock(&sess->sess_cmd_lock);
spin_lock(&cmd->t_state_lock);
if (!(cmd->transport_state & CMD_T_ACTIVE)) {
if (!(cmd->transport_state & CMD_T_ACTIVE) ||
(cmd->transport_state & CMD_T_FABRIC_STOP)) {
spin_unlock(&cmd->t_state_lock);
spin_unlock(&sess->sess_cmd_lock);
continue;
@ -240,15 +255,22 @@ static void core_tmr_drain_tmr_list(
spin_unlock(&sess->sess_cmd_lock);
continue;
}
if (sess->sess_tearing_down || cmd->cmd_wait_set) {
spin_unlock(&cmd->t_state_lock);
spin_unlock(&sess->sess_cmd_lock);
continue;
}
cmd->transport_state |= CMD_T_ABORTED;
spin_unlock(&cmd->t_state_lock);
rc = kref_get_unless_zero(&cmd->cmd_kref);
spin_unlock(&sess->sess_cmd_lock);
if (!rc) {
printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
spin_unlock(&sess->sess_cmd_lock);
continue;
}
spin_unlock(&sess->sess_cmd_lock);
list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
}
spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
@ -325,7 +347,7 @@ static void core_tmr_drain_state_list(
continue;
spin_lock(&sess->sess_cmd_lock);
rc = __target_check_io_state(cmd);
rc = __target_check_io_state(cmd, tmr_sess, tas);
spin_unlock(&sess->sess_cmd_lock);
if (!rc)
continue;
@ -364,7 +386,7 @@ static void core_tmr_drain_state_list(
cancel_work_sync(&cmd->work);
transport_wait_for_tasks(cmd);
core_tmr_handle_tas_abort(tmr_sess, cmd, tas);
core_tmr_handle_tas_abort(cmd, tas);
target_put_sess_cmd(cmd);
}
}

159
drivers/target/target_core_transport.c
View File

@ -2431,18 +2431,33 @@ static void transport_write_pending_qf(struct se_cmd *cmd)
}
}
static bool
__transport_wait_for_tasks(struct se_cmd *, bool, bool *, bool *,
unsigned long *flags);
static void target_wait_free_cmd(struct se_cmd *cmd, bool *aborted, bool *tas)
{
unsigned long flags;
spin_lock_irqsave(&cmd->t_state_lock, flags);
__transport_wait_for_tasks(cmd, true, aborted, tas, &flags);
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
}
int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
{
int ret = 0;
bool aborted = false, tas = false;
if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) {
if (wait_for_tasks && (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
transport_wait_for_tasks(cmd);
target_wait_free_cmd(cmd, &aborted, &tas);
ret = transport_put_cmd(cmd);
if (!aborted || tas)
ret = transport_put_cmd(cmd);
} else {
if (wait_for_tasks)
transport_wait_for_tasks(cmd);
target_wait_free_cmd(cmd, &aborted, &tas);
/*
* Handle WRITE failure case where transport_generic_new_cmd()
* has already added se_cmd to state_list, but fabric has
@ -2454,7 +2469,20 @@ int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
if (cmd->se_lun)
transport_lun_remove_cmd(cmd);
ret = transport_put_cmd(cmd);
if (!aborted || tas)
ret = transport_put_cmd(cmd);
}
/*
* If the task has been internally aborted due to TMR ABORT_TASK
* or LUN_RESET, target_core_tmr.c is responsible for performing
* the remaining calls to target_put_sess_cmd(), and not the
* callers of this function.
*/
if (aborted) {
pr_debug("Detected CMD_T_ABORTED for ITT: %llu\n", cmd->tag);
wait_for_completion(&cmd->cmd_wait_comp);
cmd->se_tfo->release_cmd(cmd);
ret = 1;
}
return ret;
}
@ -2509,6 +2537,7 @@ static void target_release_cmd_kref(struct kref *kref)
struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
struct se_session *se_sess = se_cmd->se_sess;
unsigned long flags;
bool fabric_stop;
spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
if (list_empty(&se_cmd->se_cmd_list)) {
@ -2517,13 +2546,19 @@ static void target_release_cmd_kref(struct kref *kref)
se_cmd->se_tfo->release_cmd(se_cmd);
return;
}
if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) {
spin_lock(&se_cmd->t_state_lock);
fabric_stop = (se_cmd->transport_state & CMD_T_FABRIC_STOP);
spin_unlock(&se_cmd->t_state_lock);
if (se_cmd->cmd_wait_set || fabric_stop) {
list_del_init(&se_cmd->se_cmd_list);
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
target_free_cmd_mem(se_cmd);
complete(&se_cmd->cmd_wait_comp);
return;
}
list_del(&se_cmd->se_cmd_list);
list_del_init(&se_cmd->se_cmd_list);
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
target_free_cmd_mem(se_cmd);
@ -2555,6 +2590,7 @@ void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
{
struct se_cmd *se_cmd;
unsigned long flags;
int rc;
spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
if (se_sess->sess_tearing_down) {
@ -2564,8 +2600,15 @@ void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
se_sess->sess_tearing_down = 1;
list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list)
se_cmd->cmd_wait_set = 1;
list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list) {
rc = kref_get_unless_zero(&se_cmd->cmd_kref);
if (rc) {
se_cmd->cmd_wait_set = 1;
spin_lock(&se_cmd->t_state_lock);
se_cmd->transport_state |= CMD_T_FABRIC_STOP;
spin_unlock(&se_cmd->t_state_lock);
}
}
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
}
@ -2578,15 +2621,25 @@ void target_wait_for_sess_cmds(struct se_session *se_sess)
{
struct se_cmd *se_cmd, *tmp_cmd;
unsigned long flags;
bool tas;
list_for_each_entry_safe(se_cmd, tmp_cmd,
&se_sess->sess_wait_list, se_cmd_list) {
list_del(&se_cmd->se_cmd_list);
list_del_init(&se_cmd->se_cmd_list);
pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
" %d\n", se_cmd, se_cmd->t_state,
se_cmd->se_tfo->get_cmd_state(se_cmd));
spin_lock_irqsave(&se_cmd->t_state_lock, flags);
tas = (se_cmd->transport_state & CMD_T_TAS);
spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);
if (!target_put_sess_cmd(se_cmd)) {
if (tas)
target_put_sess_cmd(se_cmd);
}
wait_for_completion(&se_cmd->cmd_wait_comp);
pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
" fabric state: %d\n", se_cmd, se_cmd->t_state,
@ -2608,6 +2661,58 @@ void transport_clear_lun_ref(struct se_lun *lun)
wait_for_completion(&lun->lun_ref_comp);
}
static bool
__transport_wait_for_tasks(struct se_cmd *cmd, bool fabric_stop,
bool *aborted, bool *tas, unsigned long *flags)
__releases(&cmd->t_state_lock)
__acquires(&cmd->t_state_lock)
{
assert_spin_locked(&cmd->t_state_lock);
WARN_ON_ONCE(!irqs_disabled());
if (fabric_stop)
cmd->transport_state |= CMD_T_FABRIC_STOP;
if (cmd->transport_state & CMD_T_ABORTED)
*aborted = true;
if (cmd->transport_state & CMD_T_TAS)
*tas = true;
if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
return false;
if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
return false;
if (!(cmd->transport_state & CMD_T_ACTIVE))
return false;
if (fabric_stop && *aborted)
return false;
cmd->transport_state |= CMD_T_STOP;
pr_debug("wait_for_tasks: Stopping %p ITT: 0x%08llx i_state: %d,"
" t_state: %d, CMD_T_STOP\n", cmd, cmd->tag,
cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);
spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
wait_for_completion(&cmd->t_transport_stop_comp);
spin_lock_irqsave(&cmd->t_state_lock, *flags);
cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->"
"t_transport_stop_comp) for ITT: 0x%08llx\n", cmd->tag);
return true;
}
/**
* transport_wait_for_tasks - wait for completion to occur
* @cmd: command to wait
@ -2618,43 +2723,13 @@ void transport_clear_lun_ref(struct se_lun *lun)
bool transport_wait_for_tasks(struct se_cmd *cmd)
{
unsigned long flags;
bool ret, aborted = false, tas = false;
spin_lock_irqsave(&cmd->t_state_lock, flags);
if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
return false;
}
if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
!(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
return false;
}
if (!(cmd->transport_state & CMD_T_ACTIVE)) {
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
return false;
}
cmd->transport_state |= CMD_T_STOP;
pr_debug("wait_for_tasks: Stopping %p ITT: 0x%08llx i_state: %d, t_state: %d, CMD_T_STOP\n",
cmd, cmd->tag, cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);
ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
wait_for_completion(&cmd->t_transport_stop_comp);
spin_lock_irqsave(&cmd->t_state_lock, flags);
cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->t_transport_stop_comp) for ITT: 0x%08llx\n",
cmd->tag);
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
return true;
return ret;
}
EXPORT_SYMBOL(transport_wait_for_tasks);

2
include/target/target_core_base.h
View File

@ -493,6 +493,8 @@ struct se_cmd {
#define CMD_T_DEV_ACTIVE (1 << 7)
#define CMD_T_REQUEST_STOP (1 << 8)
#define CMD_T_BUSY (1 << 9)
#define CMD_T_TAS (1 << 10)
#define CMD_T_FABRIC_STOP (1 << 11)
spinlock_t t_state_lock;
struct kref cmd_kref;
struct completion t_transport_stop_comp;