[PATCH 5.12 582/700] scsi: iscsi: Flush block work before unblock

[Greg Kroah-Hartman]

From: Mike Christie <michael.christie@xxxxxxxxxx>

[ Upstream commit 7ce9fc5ecde0d8bd64c29baee6c5e3ce7074ec9a ]

We set the max_active iSCSI EH works to 1, so all work is going to execute
in order by default. However, userspace can now override this in sysfs. If
max_active > 1, we can end up with the block_work on CPU1 and
iscsi_unblock_session running the unblock_work on CPU2 and the session and
target/device state will end up out of sync with each other.

This adds a flush of the block_work in iscsi_unblock_session.

Link: https://lore.kernel.org/r/20210525181821.7617-17-michael.christie@xxxxxxxxxx
Fixes: 1d726aa6ef57 ("scsi: iscsi: Optimize work queue flush use")
Reviewed-by: Lee Duncan <lduncan@xxxxxxxx>
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/scsi/scsi_transport_iscsi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index b8a93e607891..6ce1cc992d1d 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -1969,6 +1969,8 @@ static void __iscsi_unblock_session(struct work_struct *work)
  */
 void iscsi_unblock_session(struct iscsi_cls_session *session)
 {
+	flush_work(&session->block_work);
+
 	queue_work(iscsi_eh_timer_workq, &session->unblock_work);
 	/*
 	 * Blocking the session can be done from any context so we only
-- 
2.30.2