From patchwork Tue Dec 17 15:54:07 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Penyaev X-Patchwork-Id: 11298035 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 02A1E138C for ; Tue, 17 Dec 2019 15:54:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DEFE62146E for ; Tue, 17 Dec 2019 15:54:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727412AbfLQPyY (ORCPT ); Tue, 17 Dec 2019 10:54:24 -0500 Received: from mx2.suse.de ([195.135.220.15]:34830 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726925AbfLQPyX (ORCPT ); Tue, 17 Dec 2019 10:54:23 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id C529CAEAF; Tue, 17 Dec 2019 15:54:21 +0000 (UTC) From: Roman Penyaev Cc: Jens Axboe , linux-block@vger.kernel.org, Roman Penyaev Subject: [PATCH 1/1] block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT Date: Tue, 17 Dec 2019 16:54:07 +0100 Message-Id: <20191217155407.928386-1-rpenyaev@suse.de> X-Mailer: git-send-email 2.24.0 MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Non-mq devs do not honor REQ_NOWAIT so give a chance to the caller to repeat request gracefully on -EAGAIN error. The problem is well reproduced using io_uring: mkfs.ext4 /dev/ram0 mount /dev/ram0 /mnt # Preallocate a file dd if=/dev/zero of=/mnt/file bs=1M count=1 # Start fio with io_uring and get -EIO fio --rw=write --ioengine=io_uring --size=1M --direct=1 --name=job --filename=/mnt/file Signed-off-by: Roman Penyaev --- block/blk-core.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index d5e668ec751b..1075aaff606d 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -886,11 +886,14 @@ generic_make_request_checks(struct bio *bio) } /* - * For a REQ_NOWAIT based request, return -EOPNOTSUPP - * if queue is not a request based queue. + * Non-mq queues do not honor REQ_NOWAIT, so complete a bio + * with BLK_STS_AGAIN status in order to catch -EAGAIN and + * to give a chance to the caller to repeat request gracefully. */ - if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q)) - goto not_supported; + if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q)) { + status = BLK_STS_AGAIN; + goto end_io; + } if (should_fail_bio(bio)) goto end_io;