From b39205d248b9c3ce0548859ed786badb2e0db0bd Mon Sep 17 00:00:00 2001 From: Tyrel Datwyler Date: Wed, 7 Dec 2016 17:31:26 -0600 Subject: [PATCH] scsi: ibmvscsi: add write memory barrier to CRQ processing The first byte of each CRQ entry is used to indicate whether an entry is a valid response or free for the VIOS to use. After processing a response the driver sets the valid byte to zero to indicate the entry is now free to be reused. Add a memory barrier after this write to ensure no other stores are reordered when updating the valid byte. Signed-off-by: Tyrel Datwyler Reviewed-by: Brian King Signed-off-by: Martin K. Petersen --- drivers/scsi/ibmvscsi/ibmvscsi.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c index 7752656..50cd011 100644 --- a/drivers/scsi/ibmvscsi/ibmvscsi.c +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c @@ -233,6 +233,7 @@ static void ibmvscsi_task(void *data) while ((crq = crq_queue_next_crq(&hostdata->queue)) != NULL) { ibmvscsi_handle_crq(crq, hostdata); crq->valid = VIOSRP_CRQ_FREE; + wmb(); } vio_enable_interrupts(vdev); @@ -241,6 +242,7 @@ static void ibmvscsi_task(void *data) vio_disable_interrupts(vdev); ibmvscsi_handle_crq(crq, hostdata); crq->valid = VIOSRP_CRQ_FREE; + wmb(); } else { done = 1; } -- 2.7.4