target: Re-instate sess_wait_list for target_wait_for_sess_cmds
Switch back to pre commit 1c7b13fe652 list splicing logic for active I/O
shutdown with tcm_qla2xxx + ib_srpt fabrics.
The original commit was done under the incorrect assumption that it's safe to
walk se_sess->sess_cmd_list unprotected in target_wait_for_sess_cmds() after
sess->sess_tearing_down = 1 has been set by target_sess_cmd_list_set_waiting()
during session shutdown.
So instead of adding sess->sess_cmd_lock protection around sess->sess_cmd_list
during target_wait_for_sess_cmds(), switch back to sess->sess_wait_list to
allow wait_for_completion() + TFO->release_cmd() to occur without having to
walk ->sess_cmd_list after the list_splice.
Also add a check to exit if target_sess_cmd_list_set_waiting() has already
been called, and add a WARN_ON to check for any fabric bug where new se_cmds
are added to sess->sess_cmd_list after sess->sess_tearing_down = 1 has already
been set.
Cc: Joern Engel <joern@logfs.org>
Cc: Roland Dreier <roland@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 311c113..bbca144 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -221,6 +221,7 @@
INIT_LIST_HEAD(&se_sess->sess_list);
INIT_LIST_HEAD(&se_sess->sess_acl_list);
INIT_LIST_HEAD(&se_sess->sess_cmd_list);
+ INIT_LIST_HEAD(&se_sess->sess_wait_list);
spin_lock_init(&se_sess->sess_cmd_lock);
kref_init(&se_sess->sess_kref);
@@ -2250,11 +2251,14 @@
unsigned long flags;
spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
-
- WARN_ON(se_sess->sess_tearing_down);
+ if (se_sess->sess_tearing_down) {
+ spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
+ return;
+ }
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_cmd_list, se_cmd_list)
+ list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list)
se_cmd->cmd_wait_set = 1;
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
@@ -2267,9 +2271,10 @@
void target_wait_for_sess_cmds(struct se_session *se_sess)
{
struct se_cmd *se_cmd, *tmp_cmd;
+ unsigned long flags;
list_for_each_entry_safe(se_cmd, tmp_cmd,
- &se_sess->sess_cmd_list, se_cmd_list) {
+ &se_sess->sess_wait_list, se_cmd_list) {
list_del(&se_cmd->se_cmd_list);
pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
@@ -2283,6 +2288,11 @@
se_cmd->se_tfo->release_cmd(se_cmd);
}
+
+ spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
+ WARN_ON(!list_empty(&se_sess->sess_cmd_list));
+ spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
+
}
EXPORT_SYMBOL(target_wait_for_sess_cmds);