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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

drivers/scsi/ibmvscsi/ibmvscsi.c

+10 −0
Original line number Diff line number Diff line
@@ -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);

}