3.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
commit 9b31a328e344e62e7cc98ae574edcb7b674719bb upstream.
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.
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Cc: Joern Engel <joern@xxxxxxxxx>
Cc: Roland Dreier <roland@xxxxxxxxxx>
Signed-off-by: Lingzhu Xiang <lxiang@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/target/target_core_transport.c | 18 ++++++++++++++----
include/target/target_core_base.h | 1 +
2 files changed, 15 insertions(+), 4 deletions(-)
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -222,6 +222,7 @@ struct se_session *transport_init_sessio
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);
@@ -2252,11 +2253,14 @@ void target_sess_cmd_list_set_waiting(st
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);
@@ -2273,9 +2277,10 @@ void target_wait_for_sess_cmds(
{
struct se_cmd *se_cmd, *tmp_cmd;
bool rc = false;
+ 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:"
@@ -2303,6 +2308,11 @@ void target_wait_for_sess_cmds(
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);
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -544,6 +544,7 @@ struct se_session {
struct list_head sess_list;
struct list_head sess_acl_list;
struct list_head sess_cmd_list;
+ struct list_head sess_wait_list;
spinlock_t sess_cmd_lock;
struct kref sess_kref;
};
--
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