scsi: core: Avoid leaving shost->last_reset with stale value if EH does not run

The changes to issue the abort from the scmd->abort_work instead of the EH
thread introduced a problem if eh_deadline is used.  If aborting the
command(s) is successful, and there are never any scmds added to the
shost->eh_cmd_q, there is no code path which will reset the ->last_reset
value back to zero.

The effect of this is that after a successful abort with no EH thread
activity, a subsequent timeout, perhaps a long time later, might
immediately be considered past a user-set eh_deadline time, and the host
will be reset with no attempt at recovery.

Fix this by resetting ->last_reset back to zero in scmd_eh_abort_handler()
if it is determined that the EH thread will not run to do this.

Thanks to Gopinath Marappan for investigating this problem.

Link: https://lore.kernel.org/r/20211029194311.17504-2-emilne@redhat.com
Fixes: e494f6a72839 ("[SCSI] improved eh timeout handler")
Cc: stable@vger.kernel.org
Signed-off-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 7958a604f979..29ac40cf1aae 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -73,7 +73,7 @@ enum scsi_cmnd_submitter {
 struct scsi_cmnd {
 	struct scsi_request req;
 	struct scsi_device *device;
-	struct list_head eh_entry; /* entry for the host eh_cmd_q */
+	struct list_head eh_entry; /* entry for the host eh_abort_list/eh_cmd_q */
 	struct delayed_work abort_work;
 
 	struct rcu_head rcu;