From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754717AbdBPMI0 (ORCPT ); Thu, 16 Feb 2017 07:08:26 -0500 Received: from mx2.suse.de ([195.135.220.15]:52184 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754420AbdBPMIY (ORCPT ); Thu, 16 Feb 2017 07:08:24 -0500 Subject: Re: [PATCH 02/17] block: introduce bio_remove_last_page() To: Ming Lei , Shaohua Li , Jens Axboe , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, linux-block@vger.kernel.org, Christoph Hellwig , NeilBrown References: <1487245547-24384-1-git-send-email-tom.leiming@gmail.com> <1487245547-24384-3-git-send-email-tom.leiming@gmail.com> From: Johannes Thumshirn Message-ID: Date: Thu, 16 Feb 2017 13:08:22 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <1487245547-24384-3-git-send-email-tom.leiming@gmail.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/16/2017 12:45 PM, Ming Lei wrote: > MD need this helper to remove the last added page, so introduce > it. > > Signed-off-by: Ming Lei > --- > block/bio.c | 23 +++++++++++++++++++++++ > include/linux/bio.h | 1 + > 2 files changed, 24 insertions(+) > > diff --git a/block/bio.c b/block/bio.c > index 5eec5e08417f..0ce7ffcd7939 100644 > --- a/block/bio.c > +++ b/block/bio.c > @@ -837,6 +837,29 @@ int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page > EXPORT_SYMBOL(bio_add_pc_page); > > /** > + * bio_remove_last_page - remove the last added page > + * @bio: destination bio > + * > + * Attempt to remove the last added page from the bio_vec maplist. > + */ > +void bio_remove_last_page(struct bio *bio) > +{ > + /* > + * cloned bio must not modify vec list > + */ > + if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) > + return; > + > + if (bio->bi_vcnt > 0) { In patch 1 you introduce bio_segments_all() with the log message 'So that we can replace the direct access to .bi_vcnt.' Here you introduce a new direct access to it (plus the duplicated WARN_ON_ONCE()). Maybe use the helper directly here (I admit I haven't gone through the whole series yet, so I can't see if the change is made later). Byte, Johannes -- Johannes Thumshirn Storage jthumshirn@suse.de +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850