From patchwork Mon Jul 23 14:37:50 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Keith Busch X-Patchwork-Id: 10540391 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5B782112E for ; Mon, 23 Jul 2018 14:38:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4BB6E28BD8 for ; Mon, 23 Jul 2018 14:38:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3FC0528BE1; Mon, 23 Jul 2018 14:38:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E382328BD8 for ; Mon, 23 Jul 2018 14:38:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388217AbeGWPjl (ORCPT ); Mon, 23 Jul 2018 11:39:41 -0400 Received: from mga06.intel.com ([134.134.136.31]:7026 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387910AbeGWPjk (ORCPT ); Mon, 23 Jul 2018 11:39:40 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Jul 2018 07:38:06 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,393,1526367600"; d="scan'208";a="75161400" Received: from unknown (HELO localhost.lm.intel.com) ([10.232.112.44]) by orsmga001.jf.intel.com with ESMTP; 23 Jul 2018 07:37:52 -0700 From: Keith Busch To: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org Cc: linux-nvme@lists.infradead.org, Christoph Hellwig , Jens Axboe , Jianchao Wang , Bart Van Assche , Keith Busch Subject: [PATCHv2 1/2] blk-mq: export setting request completion state Date: Mon, 23 Jul 2018 08:37:50 -0600 Message-Id: <20180723143751.10843-1-keith.busch@intel.com> X-Mailer: git-send-email 2.13.6 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This is preparing for drivers that want to directly alter the state of their requests. No functional change here. Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig --- v1 -> v2: Reversed the return value: 'true' for success instead of failure. Document the caller's responsibilities after a successful state transtion. block/blk-mq.c | 4 +--- include/linux/blk-mq.h | 14 ++++++++++++++ 2 files changed, 15 insertions(+), 3 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 22326612a5d3..8f01cd7fd182 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -558,10 +558,8 @@ static void __blk_mq_complete_request(struct request *rq) bool shared = false; int cpu; - if (cmpxchg(&rq->state, MQ_RQ_IN_FLIGHT, MQ_RQ_COMPLETE) != - MQ_RQ_IN_FLIGHT) + if (!blk_mq_mark_complete(rq)) return; - if (rq->internal_tag != -1) blk_mq_sched_completed_request(rq); diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 9b0fd11ce89a..4d41ed16314c 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -289,6 +289,20 @@ void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues); void blk_mq_quiesce_queue_nowait(struct request_queue *q); +/** + * blk_mq_mark_complete() - Set request state to complete + * @rq: request to set to complete state + * + * Returns true if request state was successfully set to complete. If + * successful, the caller is responsibile for seeing this request is ended, as + * blk_mq_complete_request will not work again. + */ +static inline bool blk_mq_mark_complete(struct request *rq) +{ + return cmpxchg(&rq->state, MQ_RQ_IN_FLIGHT, MQ_RQ_COMPLETE) == + MQ_RQ_IN_FLIGHT; +} + /* * Driver command data is immediately after the request. So subtract request * size to get back to the original request, add request size to get the PDU. From patchwork Mon Jul 23 14:37:51 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Keith Busch X-Patchwork-Id: 10540389 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1E48C90E3 for ; Mon, 23 Jul 2018 14:38:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0F95028BDC for ; Mon, 23 Jul 2018 14:38:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0388E28BE2; Mon, 23 Jul 2018 14:38:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A5D6B28BE1 for ; Mon, 23 Jul 2018 14:38:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388192AbeGWPjk (ORCPT ); Mon, 23 Jul 2018 11:39:40 -0400 Received: from mga06.intel.com ([134.134.136.31]:7026 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388113AbeGWPjk (ORCPT ); Mon, 23 Jul 2018 11:39:40 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Jul 2018 07:38:06 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,393,1526367600"; d="scan'208";a="75161401" Received: from unknown (HELO localhost.lm.intel.com) ([10.232.112.44]) by orsmga001.jf.intel.com with ESMTP; 23 Jul 2018 07:37:53 -0700 From: Keith Busch To: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org Cc: linux-nvme@lists.infradead.org, Christoph Hellwig , Jens Axboe , Jianchao Wang , Bart Van Assche , Keith Busch Subject: [PATCHv2 2/2] scsi: set timed out out mq requests to complete Date: Mon, 23 Jul 2018 08:37:51 -0600 Message-Id: <20180723143751.10843-2-keith.busch@intel.com> X-Mailer: git-send-email 2.13.6 In-Reply-To: <20180723143751.10843-1-keith.busch@intel.com> References: <20180723143751.10843-1-keith.busch@intel.com> Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The scsi block layer requires requests claimed by the error handling be completed by the error handler. A previous commit allowed completions to proceed for blk-mq, breaking that assumption. This patch prevents completions that may race with the timeout handler by marking the state to complete, restoring the previous behavior. Fixes: 12f5b931 ("blk-mq: Remove generation seqeunce") Signed-off-by: Keith Busch Reviewed-by: Christoph Hellwig --- v1 -> v2: Document why this is necessary in code comments. Update to API's changed return value drivers/scsi/scsi_error.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 8932ae81a15a..2715cdaa669c 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -296,6 +296,20 @@ enum blk_eh_timer_return scsi_times_out(struct request *req) rtn = host->hostt->eh_timed_out(scmd); if (rtn == BLK_EH_DONE) { + /* + * For blk-mq, we must set the request state to complete now + * before sending the request to the scsi error handler. This + * will prevent a use-after-free in the event the LLD manages + * to complete the request before the error handler finishes + * processing this timed out request. + * + * If the request was already completed, then the LLD beat the + * time out handler from transferring the request to the scsi + * error handler. In that case we can return immediately as no + * further action is required. + */ + if (req->q->mq_ops && !blk_mq_mark_complete(req)) + return rtn; if (scsi_abort_command(scmd) != SUCCESS) { set_host_byte(scmd, DID_TIME_OUT); scsi_eh_scmd_add(scmd);