From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3tYvsw73q6zDw2m for ; Thu, 8 Dec 2016 10:32:20 +1100 (AEDT) Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uB7NU2Pb005176 for ; Wed, 7 Dec 2016 18:32:18 -0500 Received: from e19.ny.us.ibm.com (e19.ny.us.ibm.com [129.33.205.209]) by mx0a-001b2d01.pphosted.com with ESMTP id 276r41jwtp-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 07 Dec 2016 18:32:18 -0500 Received: from localhost by e19.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 7 Dec 2016 18:32:17 -0500 From: Tyrel Datwyler To: james.bottomley@hansenpartnership.com Cc: martin.petersen@oracle.com, linux-scsi@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, brking@linux.vnet.ibm.com, nfont@linux.vnet.ibm.com, Tyrel Datwyler Subject: [PATCH] ibmvscsi: add write memory barrier to CRQ processing Date: Wed, 7 Dec 2016 17:31:26 -0600 Message-Id: <1481153486-5185-1-git-send-email-tyreld@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , The first byte of each CRQ entry is used to indicate whether an entry is a valid response or free for the VIOS to use. After processing a response the driver sets the valid byte to zero to indicate the entry is now free to be reused. Add a memory barrier after this write to ensure no other stores are reordered when updating the valid byte. Signed-off-by: Tyrel Datwyler --- drivers/scsi/ibmvscsi/ibmvscsi.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c index d9534ee..2f5b07e 100644 --- a/drivers/scsi/ibmvscsi/ibmvscsi.c +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c @@ -232,6 +232,7 @@ static void ibmvscsi_task(void *data) while ((crq = crq_queue_next_crq(&hostdata->queue)) != NULL) { ibmvscsi_handle_crq(crq, hostdata); crq->valid = VIOSRP_CRQ_FREE; + wmb(); } vio_enable_interrupts(vdev); @@ -240,6 +241,7 @@ static void ibmvscsi_task(void *data) vio_disable_interrupts(vdev); ibmvscsi_handle_crq(crq, hostdata); crq->valid = VIOSRP_CRQ_FREE; + wmb(); } else { done = 1; } -- 1.8.3.1