Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934516AbaGXKKf (ORCPT ); Thu, 24 Jul 2014 06:10:35 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:54897 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934541AbaGXJr6 (ORCPT ); Thu, 24 Jul 2014 05:47:58 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Brian King , Christoph Hellwig , Luis Henriques Subject: [PATCH 3.11 065/128] ibmvscsi: Add memory barriers for send / receive Date: Thu, 24 Jul 2014 10:45:14 +0100 Message-Id: <1406195177-8656-66-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1406195177-8656-1-git-send-email-luis.henriques@canonical.com> References: <1406195177-8656-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11.10.14 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Brian King 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 Acked-by: Nathan Fontenot Signed-off-by: Christoph Hellwig Signed-off-by: Luis Henriques --- drivers/scsi/ibmvscsi/ibmvscsi.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c index 1e29efc8271a..c62b3e5d44bd 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); } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/