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=-16.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 4483EC4338F for ; Tue, 27 Jul 2021 10:06:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2089761406 for ; Tue, 27 Jul 2021 10:06:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236168AbhG0KG4 (ORCPT ); Tue, 27 Jul 2021 06:06:56 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:50205 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236105AbhG0KG4 (ORCPT ); Tue, 27 Jul 2021 06:06:56 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1627380416; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=wBIadlePi1nhhZbqCiG2KIXwtjptI0cXgbqATL0nsZI=; b=CgwveBxA85CRaYvF/jM15+ZZx1pyuUpe6gzLFFcZRgFSidicGGUQGQgItxY8jB1ghJkJAo U+ourGBunp4PsZKosra3kXjYH072bvjRSo/ZrtFDBf2tr4PNKpVgmmd9W/ibGVfsxnMzby Lnw5twUZboCEhY+fHOvKiiX8yYO40MQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-150-dHXDFyHZNze4RbAXe7PVww-1; Tue, 27 Jul 2021 06:06:55 -0400 X-MC-Unique: dHXDFyHZNze4RbAXe7PVww-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1B2F61853027; Tue, 27 Jul 2021 10:06:54 +0000 (UTC) Received: from T590 (ovpn-12-42.pek2.redhat.com [10.72.12.42]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B733C5DAA5; Tue, 27 Jul 2021 10:06:48 +0000 (UTC) Date: Tue, 27 Jul 2021 18:06:46 +0800 From: Ming Lei To: John Garry Cc: axboe@kernel.dk, osandov@fb.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] blk-mq-sched: Fix blk_mq_sched_alloc_tags() error handling Message-ID: References: <1627378373-148090-1-git-send-email-john.garry@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1627378373-148090-1-git-send-email-john.garry@huawei.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Jul 27, 2021 at 05:32:53PM +0800, John Garry wrote: > If the blk_mq_sched_alloc_tags() -> blk_mq_alloc_rqs() call fails, then we > call blk_mq_sched_free_tags() -> blk_mq_free_rqs(). > > It is incorrect to do so, as any rqs would have already been freed in the > blk_mq_alloc_rqs() call. > > Fix by calling blk_mq_free_rq_map() only directly. > > Fixes: 6917ff0b5bd41 ("blk-mq-sched: refactor scheduler initialization") > Signed-off-by: John Garry Not sure it is one fix, because blk_mq_free_rqs() does nothing when ->static_rqs[] isn't filled, so 'Fixes' tag isn't needed, IMO. > > diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c > index c838d81ac058..0f006cabfd91 100644 > --- a/block/blk-mq-sched.c > +++ b/block/blk-mq-sched.c > @@ -515,17 +515,6 @@ void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx, > percpu_ref_put(&q->q_usage_counter); > } > > -static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set, > - struct blk_mq_hw_ctx *hctx, > - unsigned int hctx_idx) > -{ > - if (hctx->sched_tags) { > - blk_mq_free_rqs(set, hctx->sched_tags, hctx_idx); > - blk_mq_free_rq_map(hctx->sched_tags, set->flags); > - hctx->sched_tags = NULL; > - } > -} > - > static int blk_mq_sched_alloc_tags(struct request_queue *q, > struct blk_mq_hw_ctx *hctx, > unsigned int hctx_idx) > @@ -539,8 +528,10 @@ static int blk_mq_sched_alloc_tags(struct request_queue *q, > return -ENOMEM; > > ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests); > - if (ret) > - blk_mq_sched_free_tags(set, hctx, hctx_idx); > + if (ret) { > + blk_mq_free_rq_map(hctx->sched_tags, set->flags); > + hctx->sched_tags = NULL; > + } The patch itself looks fine: Reviewed-by: Ming Lei Thanks, Ming