From patchwork Thu Sep 9 14:12:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yu Kuai X-Patchwork-Id: 12483207 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 0EFC5C433EF for ; Thu, 9 Sep 2021 14:03:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB2B9610CE for ; Thu, 9 Sep 2021 14:03:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236092AbhIIOE7 (ORCPT ); Thu, 9 Sep 2021 10:04:59 -0400 Received: from szxga03-in.huawei.com ([45.249.212.189]:15314 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347029AbhIIOEK (ORCPT ); Thu, 9 Sep 2021 10:04:10 -0400 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.55]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4H510f4JLbz8srZ; Thu, 9 Sep 2021 22:02:26 +0800 (CST) Received: from dggema762-chm.china.huawei.com (10.1.198.204) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2308.8; Thu, 9 Sep 2021 22:02:57 +0800 Received: from huawei.com (10.175.127.227) by dggema762-chm.china.huawei.com (10.1.198.204) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.8; Thu, 9 Sep 2021 22:02:56 +0800 From: Yu Kuai To: , , , CC: , , , , Subject: [PATCH v5 4/6] blk-mq: export two symbols to get request by tag Date: Thu, 9 Sep 2021 22:12:54 +0800 Message-ID: <20210909141256.2606682-5-yukuai3@huawei.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210909141256.2606682-1-yukuai3@huawei.com> References: <20210909141256.2606682-1-yukuai3@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.127.227] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggema762-chm.china.huawei.com (10.1.198.204) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org nbd has a defect that blk_mq_tag_to_rq() might return a freed request in nbd_read_stat(). We need a new mechanism if we want to fix this in nbd driver, which is rather complicated. Thus use blk_mq_find_and_get_req() to replace blk_mq_tag_to_rq(), which can make sure the returned request is not freed, and then we can do more checking while 'cmd->lock' is hold. Signed-off-by: Yu Kuai --- block/blk-mq-tag.c | 5 +++-- block/blk-mq.c | 1 + include/linux/blk-mq.h | 3 +++ 3 files changed, 7 insertions(+), 2 deletions(-) diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index 86f87346232a..b4f66b75b4d1 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -200,8 +200,8 @@ struct bt_iter_data { bool reserved; }; -static struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags, - unsigned int bitnr) +struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags, + unsigned int bitnr) { struct request *rq; unsigned long flags; @@ -213,6 +213,7 @@ static struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags, spin_unlock_irqrestore(&tags->lock, flags); return rq; } +EXPORT_SYMBOL(blk_mq_find_and_get_req); static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data) { diff --git a/block/blk-mq.c b/block/blk-mq.c index 08626cb0534c..5113aa3788a2 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -916,6 +916,7 @@ void blk_mq_put_rq_ref(struct request *rq) else if (refcount_dec_and_test(&rq->ref)) __blk_mq_free_request(rq); } +EXPORT_SYMBOL(blk_mq_put_rq_ref); static bool blk_mq_check_expired(struct blk_mq_hw_ctx *hctx, struct request *rq, void *priv, bool reserved) diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 13ba1861e688..03e02990609d 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -637,4 +637,7 @@ blk_qc_t blk_mq_submit_bio(struct bio *bio); void blk_mq_hctx_set_fq_lock_class(struct blk_mq_hw_ctx *hctx, struct lock_class_key *key); +void blk_mq_put_rq_ref(struct request *rq); +struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags, + unsigned int bitnr); #endif