From patchwork Mon Nov 30 19:07:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Falcon X-Patchwork-Id: 335681 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8F557C63777 for ; Mon, 30 Nov 2020 19:08:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1300920691 for ; Mon, 30 Nov 2020 19:08:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="STeElyyg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388213AbgK3TIX (ORCPT ); Mon, 30 Nov 2020 14:08:23 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:39140 "EHLO mx0b-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726026AbgK3TIX (ORCPT ); Mon, 30 Nov 2020 14:08:23 -0500 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0AUJ1mNf164833; Mon, 30 Nov 2020 14:07:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=pp1; bh=EZWTFGro04oEtz5pg4Ckd/01mafqCzMu7ZNtjhdnNOk=; b=STeElyygk9FcMI0ALiWarl5ibmcuIlgCsAKpUlaq2jVrE9RKwF7B2ur2dncl2KD/bvYQ OC678+nGaFsaRVnLn/+4LbBaqZXo/WUNedq5aaAYrZ9m18mrompjogLJJm4e62L71Crq u0YBVKsyZXvD2j113zCwqiFYTk8PX4w8RkfpFEljwBTewxui/iJrPBSZRLNKmDIcDr4B TGZpkepShqgOQFKfbCi72Xacn+yUV4UvMntlmVrnebS0r9hDB8OgI2LFGcyAS41mPY/d 1CjaMfHuTgKZiEie5KYtCtYogbZlislPWfIS+qBATmIGz/p7v6DPgJyripdd8CVFsrC6 mg== Received: from ppma02wdc.us.ibm.com (aa.5b.37a9.ip4.static.sl-reverse.com [169.55.91.170]) by mx0a-001b2d01.pphosted.com with ESMTP id 3556640t9x-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 30 Nov 2020 14:07:32 -0500 Received: from pps.filterd (ppma02wdc.us.ibm.com [127.0.0.1]) by ppma02wdc.us.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 0AUJ28Eg012973; Mon, 30 Nov 2020 19:07:32 GMT Received: from b01cxnp23032.gho.pok.ibm.com (b01cxnp23032.gho.pok.ibm.com [9.57.198.27]) by ppma02wdc.us.ibm.com with ESMTP id 353e68t2bg-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 30 Nov 2020 19:07:32 +0000 Received: from b01ledav001.gho.pok.ibm.com (b01ledav001.gho.pok.ibm.com [9.57.199.106]) by b01cxnp23032.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 0AUJ7Vko50594302 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 30 Nov 2020 19:07:31 GMT Received: from b01ledav001.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4D0812805E; Mon, 30 Nov 2020 19:07:31 +0000 (GMT) Received: from b01ledav001.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3449628065; Mon, 30 Nov 2020 19:07:30 +0000 (GMT) Received: from oc7186267434.ibm.com (unknown [9.160.4.131]) by b01ledav001.gho.pok.ibm.com (Postfix) with ESMTP; Mon, 30 Nov 2020 19:07:30 +0000 (GMT) From: Thomas Falcon To: mpe@ellerman.id.au Cc: netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, cforno12@linux.ibm.com, ljp@linux.vnet.ibm.com, ricklind@linux.ibm.com, dnbanerg@us.ibm.com, drt@linux.vnet.ibm.com, brking@linux.vnet.ibm.com, sukadev@linux.vnet.ibm.com, tlfalcon@linux.ibm.com Subject: [PATCH net v2 1/2] ibmvnic: Ensure that SCRQ entry reads are correctly ordered Date: Mon, 30 Nov 2020 13:07:23 -0600 Message-Id: <1606763244-28111-2-git-send-email-tlfalcon@linux.ibm.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1606763244-28111-1-git-send-email-tlfalcon@linux.ibm.com> References: <1606763244-28111-1-git-send-email-tlfalcon@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312, 18.0.737 definitions=2020-11-30_08:2020-11-30,2020-11-30 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=1 clxscore=1015 phishscore=0 adultscore=0 impostorscore=0 lowpriorityscore=0 mlxscore=0 bulkscore=0 mlxlogscore=999 spamscore=0 malwarescore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011300120 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Ensure that received Subordinate Command-Response Queue (SCRQ) entries are properly read in order by the driver. These queues are used in the ibmvnic device to process RX buffer and TX completion descriptors. dma_rmb barriers have been added after checking for a pending descriptor to ensure the correct descriptor entry is checked and after reading the SCRQ descriptor to ensure the entire descriptor is read before processing. Fixes: 032c5e828 ("Driver for IBM System i/p VNIC protocol") Signed-off-by: Thomas Falcon --- drivers/net/ethernet/ibm/ibmvnic.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c index 2aa40b2..5ea9f5c 100644 --- a/drivers/net/ethernet/ibm/ibmvnic.c +++ b/drivers/net/ethernet/ibm/ibmvnic.c @@ -2403,6 +2403,12 @@ static int ibmvnic_poll(struct napi_struct *napi, int budget) if (!pending_scrq(adapter, adapter->rx_scrq[scrq_num])) break; + /* The queue entry at the current index is peeked at above + * to determine that there is a valid descriptor awaiting + * processing. We want to be sure that the current slot + * holds a valid descriptor before reading its contents. + */ + dma_rmb(); next = ibmvnic_next_scrq(adapter, adapter->rx_scrq[scrq_num]); rx_buff = (struct ibmvnic_rx_buff *)be64_to_cpu(next-> @@ -3098,6 +3104,13 @@ static int ibmvnic_complete_tx(struct ibmvnic_adapter *adapter, unsigned int pool = scrq->pool_index; int num_entries = 0; + /* The queue entry at the current index is peeked at above + * to determine that there is a valid descriptor awaiting + * processing. We want to be sure that the current slot + * holds a valid descriptor before reading its contents. + */ + dma_rmb(); + next = ibmvnic_next_scrq(adapter, scrq); for (i = 0; i < next->tx_comp.num_comps; i++) { if (next->tx_comp.rcs[i]) { @@ -3498,6 +3511,11 @@ static union sub_crq *ibmvnic_next_scrq(struct ibmvnic_adapter *adapter, } spin_unlock_irqrestore(&scrq->lock, flags); + /* Ensure that the entire buffer descriptor has been + * loaded before reading its contents + */ + dma_rmb(); + return entry; }