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authorNicholas Bellinger <nab@linux-iscsi.org>2013-05-15 00:52:44 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2013-05-29 21:30:33 -0700
commit9b31a328e344e62e7cc98ae574edcb7b674719bb (patch)
tree07baf7e2854dcd8f08066e7285ee68a89a4b9ff8
parentbe646c2d2ba8e2e56596d72633705f8286698c25 (diff)
downloadlinux-9b31a328e344e62e7cc98ae574edcb7b674719bb.tar.gz
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>
-rw-r--r--drivers/target/target_core_transport.c18
-rw-r--r--include/target/target_core_base.h1
2 files changed, 15 insertions, 4 deletions
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 311c11349aa..bbca144821c 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -221,6 +221,7 @@ struct se_session *transport_init_session(void)
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 @@ void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
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 @@ EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
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 @@ void target_wait_for_sess_cmds(struct se_session *se_sess)
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);
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index e773dfa5f98..4ea4f985f39 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -543,6 +543,7 @@ 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;
};