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authorNicholas Bellinger <nab@linux-iscsi.org>2016-01-12 08:31:09 +0300
committerNicholas Bellinger <nab@linux-iscsi.org>2016-02-04 01:09:07 +0300
commitfebe562c20dfa8f33bee7d419c6b517986a5aa33 (patch)
tree8fab8d2713f877b4464739b302bda4b21c12436b /drivers/target/target_core_tmr.c
parenta07100e00ac42a4474530ce17b4978c9e06bde55 (diff)
downloadlinux-febe562c20dfa8f33bee7d419c6b517986a5aa33.tar.xz
target: Fix LUN_RESET active I/O handling for ACK_KREF
This patch fixes a NULL pointer se_cmd->cmd_kref < 0 refcount bug during TMR LUN_RESET with active se_cmd I/O, that can be triggered during se_cmd descriptor shutdown + release via core_tmr_drain_state_list() code. To address this bug, add common __target_check_io_state() helper for ABORT_TASK + LUN_RESET w/ CMD_T_COMPLETE checking, and set CMD_T_ABORTED + obtain ->cmd_kref for both cases ahead of last target_put_sess_cmd() after TFO->aborted_task() -> transport_cmd_finish_abort() callback has completed. It also introduces SCF_ACK_KREF to determine when transport_cmd_finish_abort() needs to drop the second extra reference, ahead of calling target_put_sess_cmd() for the final kref_put(&se_cmd->cmd_kref). It also updates transport_cmd_check_stop() to avoid holding se_cmd->t_state_lock while dropping se_cmd device state via target_remove_from_state_list(), now that core_tmr_drain_state_list() is holding the se_device lock while checking se_cmd state from within TMR logic. Finally, move transport_put_cmd() release of SGL + TMR + extended CDB memory into target_free_cmd_mem() in order to avoid potential resource leaks in TMR ABORT_TASK + LUN_RESET code-paths. Also update target_release_cmd_kref() accordingly. Reviewed-by: 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@linux-iscsi.org>
Diffstat (limited to 'drivers/target/target_core_tmr.c')
-rw-r--r--drivers/target/target_core_tmr.c69
1 files changed, 46 insertions, 23 deletions
diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
index fcdcb117c60d..fb3decc28589 100644
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -107,6 +107,34 @@ static int target_check_cdb_and_preempt(struct list_head *list,
return 1;
}
+static bool __target_check_io_state(struct se_cmd *se_cmd)
+{
+ struct se_session *sess = se_cmd->se_sess;
+
+ assert_spin_locked(&sess->sess_cmd_lock);
+ 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.
+ *
+ * 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,"
+ " skipping\n", se_cmd->tag);
+ spin_unlock(&se_cmd->t_state_lock);
+ return false;
+ }
+ se_cmd->transport_state |= CMD_T_ABORTED;
+ spin_unlock(&se_cmd->t_state_lock);
+
+ return kref_get_unless_zero(&se_cmd->cmd_kref);
+}
+
void core_tmr_abort_task(
struct se_device *dev,
struct se_tmr_req *tmr,
@@ -130,34 +158,22 @@ void core_tmr_abort_task(
if (tmr->ref_task_tag != ref_tag)
continue;
- if (!kref_get_unless_zero(&se_cmd->cmd_kref))
- continue;
-
printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",
se_cmd->se_tfo->get_fabric_name(), ref_tag);
- spin_lock(&se_cmd->t_state_lock);
- if (se_cmd->transport_state & CMD_T_COMPLETE) {
- printk("ABORT_TASK: ref_tag: %llu already complete,"
- " skipping\n", ref_tag);
- spin_unlock(&se_cmd->t_state_lock);
+ if (!__target_check_io_state(se_cmd)) {
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
-
target_put_sess_cmd(se_cmd);
-
goto out;
}
- se_cmd->transport_state |= CMD_T_ABORTED;
- spin_unlock(&se_cmd->t_state_lock);
-
list_del_init(&se_cmd->se_cmd_list);
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
cancel_work_sync(&se_cmd->work);
transport_wait_for_tasks(se_cmd);
- target_put_sess_cmd(se_cmd);
transport_cmd_finish_abort(se_cmd, true);
+ target_put_sess_cmd(se_cmd);
printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
" ref_tag: %llu\n", ref_tag);
@@ -242,8 +258,10 @@ static void core_tmr_drain_state_list(
struct list_head *preempt_and_abort_list)
{
LIST_HEAD(drain_task_list);
+ struct se_session *sess;
struct se_cmd *cmd, *next;
unsigned long flags;
+ int rc;
/*
* Complete outstanding commands with TASK_ABORTED SAM status.
@@ -282,6 +300,16 @@ static void core_tmr_drain_state_list(
if (prout_cmd == cmd)
continue;
+ sess = cmd->se_sess;
+ if (WARN_ON_ONCE(!sess))
+ continue;
+
+ spin_lock(&sess->sess_cmd_lock);
+ rc = __target_check_io_state(cmd);
+ spin_unlock(&sess->sess_cmd_lock);
+ if (!rc)
+ continue;
+
list_move_tail(&cmd->state_list, &drain_task_list);
cmd->state_active = false;
}
@@ -289,7 +317,7 @@ static void core_tmr_drain_state_list(
while (!list_empty(&drain_task_list)) {
cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
- list_del(&cmd->state_list);
+ list_del_init(&cmd->state_list);
pr_debug("LUN_RESET: %s cmd: %p"
" ITT/CmdSN: 0x%08llx/0x%08x, i_state: %d, t_state: %d"
@@ -313,16 +341,11 @@ static void core_tmr_drain_state_list(
* loop above, but we do it down here given that
* cancel_work_sync may block.
*/
- if (cmd->t_state == TRANSPORT_COMPLETE)
- cancel_work_sync(&cmd->work);
-
- spin_lock_irqsave(&cmd->t_state_lock, flags);
- target_stop_cmd(cmd, &flags);
-
- cmd->transport_state |= CMD_T_ABORTED;
- spin_unlock_irqrestore(&cmd->t_state_lock, flags);
+ cancel_work_sync(&cmd->work);
+ transport_wait_for_tasks(cmd);
core_tmr_handle_tas_abort(tmr_nacl, cmd, tas);
+ target_put_sess_cmd(cmd);
}
}