diff options
| author | Brian King <brking@linux.vnet.ibm.com> | 2014-05-23 10:52:11 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-07-09 11:18:23 -0700 |
| commit | 9d2da49acf75f2c43847500f279fd68d802aabd4 (patch) | |
| tree | f281fd24fee35efd59a0878d54882e73a97d8a04 | |
| parent | 74dcc3a7d57ffab9ab0f7dd7f064f83868e61895 (diff) | |
| download | lwn-9d2da49acf75f2c43847500f279fd68d802aabd4.tar.gz lwn-9d2da49acf75f2c43847500f279fd68d802aabd4.zip | |
ibmvscsi: Add memory barriers for send / receive
commit 7114aae02742d6b5c5a0d39a41deb61d415d3717 upstream.
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>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 c3d4991411b2..c5bb0e0a36b9 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); } |