qla2xxx: added sess generations to detect RSCN update races
RSCN processing in qla2xxx driver can run in parallel with ELS/IO
processing. As such the decision to remove disappeared fc port's
session could be stale, because a new login sequence has occurred
since and created a brand new session.
Previous mechanism of dealing with this by delaying deletion request
was prone to erroneous deletions if the event that was supposed to
cancel the deletion never arrived or has been delayed in processing.
New mechanism relies on a time-like generation counter to serialize
RSCN updates relative to ELS/IO updates.
Cc: <stable@vger.kernel.org> # v3.18+
Signed-off-by: Alexei Potashnik <alexei@purestorage.com>
Signed-off-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/scsi/qla2xxx/qla_def.h b/drivers/scsi/qla2xxx/qla_def.h
index 08a869f..9ad819e 100644
--- a/drivers/scsi/qla2xxx/qla_def.h
+++ b/drivers/scsi/qla2xxx/qla_def.h
@@ -3586,6 +3586,11 @@
struct list_head qla_sess_op_cmd_list;
spinlock_t cmd_list_lock;
+ /* Counter to detect races between ELS and RSCN events */
+ atomic_t generation_tick;
+ /* Time when global fcport update has been scheduled */
+ int total_fcport_update_gen;
+
uint32_t vp_abort_cnt;
struct fc_vport *fc_vport; /* holds fc_vport * for each vport */