From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 A45C7C43381 for ; Fri, 15 Feb 2019 02:39:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 700C321900 for ; Fri, 15 Feb 2019 02:39:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550198342; bh=+rX6YSeAoRMM5r7BNd2h7IP68/H/CQjCsUnBIab07dk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Zh4oQOhGMa3QEzzuCBnvX8YoivTHSksJupoCIknyKcxq9ZxaHjoMLMxcSxvia4rwN Ut8q3RVrLJERQ1uZmOdcRr4VesKr62s5D9hdJLxU9Wvg/8t1RvEDmeHugKmTXNVUov zbOeYu1FFo2UaBkOR2K76o+zeib9LjbuhIFW5Rag= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731746AbfBOCKT (ORCPT ); Thu, 14 Feb 2019 21:10:19 -0500 Received: from mail.kernel.org ([198.145.29.99]:50428 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729960AbfBOCKT (ORCPT ); Thu, 14 Feb 2019 21:10:19 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F2818222C9; Fri, 15 Feb 2019 02:10:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550196617; bh=+rX6YSeAoRMM5r7BNd2h7IP68/H/CQjCsUnBIab07dk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CZVgpj1cidBOzF1r3LU6aRD1FICRx+v/fdoYfeYnBPAgeI5t+Ft+dzdI42Q2jrvOe qaauuTnir4lmQv2yRMuIuCHPZlwJpXSCBFFNZr/IoPVxCxH1u9EcKEA/zguDG9k27m GfetA5XdjQIHcmOnHIHHyAPihC5NC6YBAibqS/4E= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ming Lei , Tetsuo Handa , NeilBrown , Jens Axboe , Sasha Levin , linux-block@vger.kernel.org Subject: [PATCH AUTOSEL 4.20 49/77] block: cover another queue enter recursion via BIO_QUEUE_ENTERED Date: Thu, 14 Feb 2019 21:08:27 -0500 Message-Id: <20190215020855.176727-49-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190215020855.176727-1-sashal@kernel.org> References: <20190215020855.176727-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ming Lei [ Upstream commit 698cef173983b086977e633e46476e0f925ca01e ] Except for blk_queue_split(), bio_split() is used for splitting bio too, then the remained bio is often resubmit to queue via generic_make_request(). So the same queue enter recursion exits in this case too. Unfortunatley commit cd4a4ae4683dc2 doesn't help this case. This patch covers the above case by setting BIO_QUEUE_ENTERED before calling q->make_request_fn. In theory the per-bio flag is used to simulate one stack variable, it is just fine to clear it after q->make_request_fn is returned. Especially the same bio can't be submitted from another context. Fixes: cd4a4ae4683dc2 ("block: don't use blocking queue entered for recursive bio submits") Cc: Tetsuo Handa Cc: NeilBrown Reviewed-by: Mike Snitzer Signed-off-by: Ming Lei Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- block/blk-core.c | 11 +++++++++++ block/blk-merge.c | 10 ---------- 2 files changed, 11 insertions(+), 10 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index deb56932f8c4..22260339f66f 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2449,7 +2449,18 @@ blk_qc_t generic_make_request(struct bio *bio) /* Create a fresh bio_list for all subordinate requests */ bio_list_on_stack[1] = bio_list_on_stack[0]; bio_list_init(&bio_list_on_stack[0]); + + /* + * Since we're recursing into make_request here, ensure + * that we mark this bio as already having entered the queue. + * If not, and the queue is going away, we can get stuck + * forever on waiting for the queue reference to drop. But + * that will never happen, as we're already holding a + * reference to it. + */ + bio_set_flag(bio, BIO_QUEUE_ENTERED); ret = q->make_request_fn(q, bio); + bio_clear_flag(bio, BIO_QUEUE_ENTERED); /* sort new bios into those for a lower level * and those for the same level diff --git a/block/blk-merge.c b/block/blk-merge.c index 7695034f4b87..adfe835ab258 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -272,16 +272,6 @@ void blk_queue_split(struct request_queue *q, struct bio **bio) /* there isn't chance to merge the splitted bio */ split->bi_opf |= REQ_NOMERGE; - /* - * Since we're recursing into make_request here, ensure - * that we mark this bio as already having entered the queue. - * If not, and the queue is going away, we can get stuck - * forever on waiting for the queue reference to drop. But - * that will never happen, as we're already holding a - * reference to it. - */ - bio_set_flag(*bio, BIO_QUEUE_ENTERED); - bio_chain(split, *bio); trace_block_split(q, split, (*bio)->bi_iter.bi_sector); generic_make_request(*bio); -- 2.19.1