On 05/23/2014 10:52 AM, Brian King wrote: > Add a memory barrier prior to sending a new command to the VIOS > to ensure the VIOS does not receive stale data in the command buffer. > Also add a memory barrier when processing the CRQ for completed commands. > > Signed-off-by: Brian King <[email protected]>
Acked-by: Nathan Fontenot <[email protected]> > --- > > drivers/scsi/ibmvscsi/ibmvscsi.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff -puN drivers/scsi/ibmvscsi/ibmvscsi.c~ibmvscsi_barrier > drivers/scsi/ibmvscsi/ibmvscsi.c > --- linux/drivers/scsi/ibmvscsi/ibmvscsi.c~ibmvscsi_barrier 2014-05-23 > 10:41:35.000000000 -0500 > +++ linux-bjking1/drivers/scsi/ibmvscsi/ibmvscsi.c 2014-05-23 > 10:42:53.000000000 -0500 > @@ -185,6 +185,11 @@ static struct viosrp_crq *crq_queue_next > if (crq->valid & 0x80) { > if (++queue->cur == queue->size) > queue->cur = 0; > + > + /* Ensure the read of the valid bit occurs before reading any > + * other bits of the CRQ entry > + */ > + rmb(); > } else > crq = NULL; > spin_unlock_irqrestore(&queue->lock, flags); > @@ -203,6 +208,11 @@ static int ibmvscsi_send_crq(struct ibmv > { > struct vio_dev *vdev = to_vio_dev(hostdata->dev); > > + /* > + * Ensure the command buffer is flushed to memory before handing it > + * over to the VIOS to prevent it from fetching any stale data. > + */ > + mb(); > return plpar_hcall_norets(H_SEND_CRQ, vdev->unit_address, word1, word2); > } > > _ > -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
