diff options
| author | Brian King <brking@linux.vnet.ibm.com> | 2014-05-23 10:52:11 -0500 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2014-06-25 13:29:32 +0200 |
| commit | 7114aae02742d6b5c5a0d39a41deb61d415d3717 (patch) | |
| tree | cf6d4c0153c99b262ee07a050afb3d6262d758fd | |
| parent | 9ee755974bea2f9880e517ec985dc9dede1b3a36 (diff) | |
ibmvscsi: Add memory barriers for send / receive
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 <brking@linux.vnet.ibm.com>
Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: Christoph Hellwig <hch@lst.de>
| -rw-r--r-- | drivers/scsi/ibmvscsi/ibmvscsi.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c index 9caf9a97965..7b23f21f22f 100644 --- a/drivers/scsi/ibmvscsi/ibmvscsi.c +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c @@ -185,6 +185,11 @@ static struct viosrp_crq *crq_queue_next_crq(struct crq_queue *queue) 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 ibmvscsi_host_data *hostdata, { 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); } |