From: Dick Kennedy <dick.kennedy@broadcom.com>
Date: Fri, 1 May 2020 14:43:03 -0700
Subject: scsi: lpfc: Maintain atomic consistency of queue_claimed flag
Patch-mainline: v5.8-rc1
Git-commit: 164ba8d2df66735dd4f00d3b85d898a907fa6982
References: bsc#1164780

A previous change introduced the atomic use of queue_claimed flag for eq's
and cq's.  The code works fine, but the clearing of the queue_claimed flag
is not atomic.

Change queue_claimed = 0 into xchg(&queue_claimed, 0) to be consistent for
change under atomicity.

Link: https://lore.kernel.org/r/20200501214310.91713-3-jsmart2021@gmail.com
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/scsi/lpfc/lpfc_sli.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -538,7 +538,7 @@ lpfc_sli4_process_eq(struct lpfc_hba *ph
 	if (count > eq->EQ_max_eqe)
 		eq->EQ_max_eqe = count;
 
-	eq->queue_claimed = 0;
+	xchg(&eq->queue_claimed, 0);
 
 rearm_and_exit:
 	/* Always clear the EQ. */
@@ -13701,7 +13701,7 @@ static bool
 				"0369 No entry from completion queue "
 				"qid=%d\n", cq->queue_id);
 
-	cq->queue_claimed = 0;
+	xchg(&cq->queue_claimed, 0);
 
 rearm_and_exit:
 	phba->sli4_hba.sli4_write_cq_db(phba, cq, consumed,