From patchwork Mon Sep 12 16:53:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 12973810 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A8F6ECAAD5 for ; Mon, 12 Sep 2022 16:53:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229652AbiILQxn (ORCPT ); Mon, 12 Sep 2022 12:53:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45690 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229626AbiILQxl (ORCPT ); Mon, 12 Sep 2022 12:53:41 -0400 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 46693286F8 for ; Mon, 12 Sep 2022 09:53:41 -0700 (PDT) Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 28C8vv5s023976 for ; Mon, 12 Sep 2022 09:53:40 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding : content-type; s=facebook; bh=6Kw/BDvffn4PftytYruFc9QNt6h0V44NwW5Z6uqGXk0=; b=nV94FpkPrCmCHgu0Lc014aNPvdsjlsOYKTnVrXwZahQo+gek+olVwj45uPzBeLkXw8lh fz/oNT6tkenrpcNKObJfHshS6tUOqgUrLEc21rAxACwRKnmf5aNHbmhbIYJ8ng+omRwq 1sJZKPCY2bJaRpQae1LdSNJg9JUMkPJB+RY= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3jgrb1k2m6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 12 Sep 2022 09:53:40 -0700 Received: from twshared13579.04.prn5.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::c) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Mon, 12 Sep 2022 09:53:39 -0700 Received: by dev1180.prn1.facebook.com (Postfix, from userid 425415) id 46DBB206F89C; Mon, 12 Sep 2022 09:53:31 -0700 (PDT) From: Stefan Roesch To: , , CC: , Subject: [PATCH v1] block: blk_queue_enter() / __bio_queue_enter() must return -EAGAIN for nowait Date: Mon, 12 Sep 2022 09:53:25 -0700 Message-ID: <20220912165325.2858746-1-shr@fb.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: 1ydxG05hulY5J1izGOjKfRtliTWQ993y X-Proofpoint-GUID: 1ydxG05hulY5J1izGOjKfRtliTWQ993y X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-09-12_12,2022-09-12_02,2022-06-22_01 Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Today blk_queue_enter() and __bio_queue_enter() return -EBUSY for the nowait code path. This is not correct: they should return -EAGAIN instead. This problem was detected by fio. The following command exposed the above problem: t/io_uring -p0 -d128 -b4096 -s32 -c32 -F1 -B0 -R0 -X1 -n24 -P1 -u1 -O0 /dev/ng0n1 By applying the patch, the retry case is handled correctly in the slow path. Signed-off-by: Stefan Roesch --- block/blk-core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) base-commit: 80e78fcce86de0288793a0ef0f6acf37656ee4cf diff --git a/block/blk-core.c b/block/blk-core.c index a0d1104c5590..651057c4146b 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -295,7 +295,7 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) while (!blk_try_enter_queue(q, pm)) { if (flags & BLK_MQ_REQ_NOWAIT) - return -EBUSY; + return -EAGAIN; /* * read pair of barrier in blk_freeze_queue_start(), we need to @@ -325,7 +325,7 @@ int __bio_queue_enter(struct request_queue *q, struct bio *bio) if (test_bit(GD_DEAD, &disk->state)) goto dead; bio_wouldblock_error(bio); - return -EBUSY; + return -EAGAIN; } /*