From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Andy Grover <agrover@xxxxxxxxxx>
Cc: Mike Christie <mchristi@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 3.10+
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxx>
---
drivers/target/target_core_tmr.c | 54 ++++++++----
drivers/target/target_core_transport.c | 145 +++++++++++++++++++++++++--------
include/target/target_core_base.h | 2 +
3 files changed, 150 insertions(+), 51 deletions(-)
diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
index 3e0d77a..82a663b 100644
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -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);
}
}
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 94e372a..3441b15 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -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,
@@ -2608,53 +2661,75 @@ void transport_clear_lun_ref(struct se_lun *lun)
wait_for_completion(&lun->lun_ref_comp);
}
-/**
- * transport_wait_for_tasks - wait for completion to occur
- * @cmd: command to wait
- *
- * Called from frontend fabric context to wait for storage engine
- * to pause and/or release frontend generated struct se_cmd.
- */
-bool transport_wait_for_tasks(struct se_cmd *cmd)
+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)
{
- unsigned long flags;
- spin_lock_irqsave(&cmd->t_state_lock, flags);
+ 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)) {
- spin_unlock_irqrestore(&cmd->t_state_lock, flags);
+ !(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)) {
- spin_unlock_irqrestore(&cmd->t_state_lock, flags);
+ !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
return false;
- }
- if (!(cmd->transport_state & CMD_T_ACTIVE)) {
- spin_unlock_irqrestore(&cmd->t_state_lock, flags);
+ 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);
+ 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);
+ spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
wait_for_completion(&cmd->t_transport_stop_comp);
- spin_lock_irqsave(&cmd->t_state_lock, flags);
+ 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);
+ 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
+ *
+ * Called from frontend fabric context to wait for storage engine
+ * to pause and/or release frontend generated struct se_cmd.
+ */
+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);
+ ret = __transport_wait_for_tasks(cmd, false, &aborted, &tas, &flags);
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
- return true;
+ return ret;
}
EXPORT_SYMBOL(transport_wait_for_tasks);
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 1a76726..1579539e 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -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;
--
1.9.1
--
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