Commit 7114aae0 authored by Brian King's avatar Brian King Committed by Christoph Hellwig
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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: default avatarBrian King <brking@linux.vnet.ibm.com>
Acked-by: default avatarNathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 9ee75597
......@@ -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);
}
......
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