scsi: mpt3sas: Call cpu_relax() before calling udelay()

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>

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index 6c82435bc9cc65167854fcf727e5b9c96b07971d..27eb652b564f54117e02d257d92ab6111c9412d5 100644 (file)
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -1582,8 +1582,10 @@ mpt3sas_base_pause_mq_polling(struct MPT3SAS_ADAPTER *ioc)
         * 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);
+               }
        }
 }