Commit b39205d2 authored Dec 07, 2016 by Tyrel Datwyler Committed by Martin K. Petersen Dec 08, 2016

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 <tyreld@linux.vnet.ibm.com>
Reviewed-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

parent 15c92746

drivers/scsi/ibmvscsi/ibmvscsi.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}