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=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 4CE9EC433E3 for ; Thu, 13 Aug 2020 15:41:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 22ACC20855 for ; Thu, 13 Aug 2020 15:41:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726916AbgHMPly (ORCPT ); Thu, 13 Aug 2020 11:41:54 -0400 Received: from verein.lst.de ([213.95.11.211]:46782 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726679AbgHMPlx (ORCPT ); Thu, 13 Aug 2020 11:41:53 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id E1CC268AFE; Thu, 13 Aug 2020 17:41:51 +0200 (CEST) Date: Thu, 13 Aug 2020 17:41:51 +0200 From: Christoph Hellwig To: Ming Lei Cc: Jens Axboe , linux-block@vger.kernel.org, Christoph Hellwig , Stefano Garzarella Subject: Re: [PATCH V2 1/3] block: respect queue limit of max discard segment Message-ID: <20200813154151.GA14200@lst.de> References: <20200811234420.2297137-1-ming.lei@redhat.com> <20200811234420.2297137-2-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200811234420.2297137-2-ming.lei@redhat.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, Aug 12, 2020 at 07:44:18AM +0800, Ming Lei wrote: > When queue_max_discard_segments(q) is 1, blk_discard_mergable() will > return false for discard request, then normal request merge is applied. > However, only queue_max_segments() is checked, so max discard segment > limit isn't respected. > > Check max discard segment limit in the request merge code for fixing > the issue. > > Discard request failure of virtio_blk is fixed. > > Signed-off-by: Ming Lei > Fixes: 69840466086d ("block: fix the DISCARD request merge") > Cc: Christoph Hellwig > Cc: Stefano Garzarella > --- > block/blk-merge.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/block/blk-merge.c b/block/blk-merge.c > index 5196dc145270..d18fb88ca8bd 100644 > --- a/block/blk-merge.c > +++ b/block/blk-merge.c > @@ -533,10 +533,16 @@ int __blk_rq_map_sg(struct request_queue *q, struct request *rq, > } > EXPORT_SYMBOL(__blk_rq_map_sg); > > +static inline unsigned int blk_rq_get_max_segments(struct request *rq) > +{ > + return req_op(rq) == REQ_OP_DISCARD ? > + queue_max_discard_segments(rq->q) : queue_max_segments(rq->q); I'd go for a good old if statement here.. Otherwise looks good: Reviewed-by: Christoph Hellwig