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>
This commit is contained in:
Tyrel Datwyler 2016-12-07 17:31:26 -06:00 committed by Martin K. Petersen
parent 15c9274699
commit b39205d248
1 changed files with 2 additions and 0 deletions

View File

@ -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;
}