From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f199.google.com (mail-pg1-f199.google.com [209.85.215.199]) by kanga.kvack.org (Postfix) with ESMTP id 798656B065E for ; Thu, 15 Nov 2018 18:24:02 -0500 (EST) Received: by mail-pg1-f199.google.com with SMTP id l2-v6so14014030pgp.22 for ; Thu, 15 Nov 2018 15:24:02 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id v13sor32648844pgn.66.2018.11.15.15.24.00 for (Google Transport Security); Thu, 15 Nov 2018 15:24:00 -0800 (PST) Date: Thu, 15 Nov 2018 15:23:56 -0800 From: Omar Sandoval Subject: Re: [PATCH V10 05/19] block: introduce bvec_last_segment() Message-ID: <20181115232356.GA23238@vader> References: <20181115085306.9910-1-ming.lei@redhat.com> <20181115085306.9910-6-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181115085306.9910-6-ming.lei@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Ming Lei Cc: Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Kent Overstreet , Mike Snitzer , dm-devel@redhat.com, Alexander Viro , linux-fsdevel@vger.kernel.org, Shaohua Li , linux-raid@vger.kernel.org, linux-erofs@lists.ozlabs.org, David Sterba , linux-btrfs@vger.kernel.org, "Darrick J . Wong" , linux-xfs@vger.kernel.org, Gao Xiang , Christoph Hellwig , Theodore Ts'o , linux-ext4@vger.kernel.org, Coly Li , linux-bcache@vger.kernel.org, Boaz Harrosh , Bob Peterson , cluster-devel@redhat.com On Thu, Nov 15, 2018 at 04:52:52PM +0800, Ming Lei wrote: > BTRFS and guard_bio_eod() need to get the last singlepage segment > from one multipage bvec, so introduce this helper to make them happy. > > Cc: Dave Chinner > Cc: Kent Overstreet > Cc: Mike Snitzer > Cc: dm-devel@redhat.com > Cc: Alexander Viro > Cc: linux-fsdevel@vger.kernel.org > Cc: Shaohua Li > Cc: linux-raid@vger.kernel.org > Cc: linux-erofs@lists.ozlabs.org > Cc: David Sterba > Cc: linux-btrfs@vger.kernel.org > Cc: Darrick J. Wong > Cc: linux-xfs@vger.kernel.org > Cc: Gao Xiang > Cc: Christoph Hellwig > Cc: Theodore Ts'o > Cc: linux-ext4@vger.kernel.org > Cc: Coly Li > Cc: linux-bcache@vger.kernel.org > Cc: Boaz Harrosh > Cc: Bob Peterson > Cc: cluster-devel@redhat.com Reviewed-by: Omar Sandoval Minor comments below. > Signed-off-by: Ming Lei > --- > include/linux/bvec.h | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/include/linux/bvec.h b/include/linux/bvec.h > index 3d61352cd8cf..01616a0b6220 100644 > --- a/include/linux/bvec.h > +++ b/include/linux/bvec.h > @@ -216,4 +216,29 @@ static inline bool mp_bvec_iter_advance(const struct bio_vec *bv, > .bi_bvec_done = 0, \ > } > > +/* > + * Get the last singlepage segment from the multipage bvec and store it > + * in @seg > + */ > +static inline void bvec_last_segment(const struct bio_vec *bvec, > + struct bio_vec *seg) Indentation is all messed up here. > +{ > + unsigned total = bvec->bv_offset + bvec->bv_len; > + unsigned last_page = total / PAGE_SIZE; > + > + if (last_page * PAGE_SIZE == total) > + last_page--; I think this could just be unsigned int last_page = (total - 1) / PAGE_SIZE; > + seg->bv_page = nth_page(bvec->bv_page, last_page); > + > + /* the whole segment is inside the last page */ > + if (bvec->bv_offset >= last_page * PAGE_SIZE) { > + seg->bv_offset = bvec->bv_offset % PAGE_SIZE; > + seg->bv_len = bvec->bv_len; > + } else { > + seg->bv_offset = 0; > + seg->bv_len = total - last_page * PAGE_SIZE; > + } > +} > + > #endif /* __LINUX_BVEC_ITER_H */ > -- > 2.9.5 >