From: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Date: Wed, 1 Sep 2021 20:55:42 +0530
Subject: scsi: mpt3sas: Call cpu_relax() before calling udelay()
Patch-mainline: v5.15-rc3
Git-commit: e4953a93104c1fb1ef7989541f9867cc276467f9
References: jsc#SLE-19730

Call cpu_relax() while waiting for the current blk-mq polling instance to
complete.

Link: https://lore.kernel.org/r/20210901152542.27866-1-sreekanth.reddy@broadcom.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Martin Wilck <mwilck@suse.com>
---
 drivers/scsi/mpt3sas/mpt3sas_base.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -1582,8 +1582,10 @@ mpt3sas_base_pause_mq_polling(struct MPT
 	 * wait for current poll to complete.
 	 */
 	for (qid = 0; qid < iopoll_q_count; qid++) {
-		while (atomic_read(&ioc->io_uring_poll_queues[qid].busy))
+		while (atomic_read(&ioc->io_uring_poll_queues[qid].busy)) {
+			cpu_relax();
 			udelay(500);
+		}
 	}
 }