Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:33826 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726910AbeKSSzg (ORCPT ); Mon, 19 Nov 2018 13:55:36 -0500 Date: Mon, 19 Nov 2018 16:32:19 +0800 From: Ming Lei To: Omar Sandoval Cc: Jens Axboe , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Dave Chinner , Kent Overstreet , linux-fsdevel@vger.kernel.org, Alexander Viro , Shaohua Li , linux-raid@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-btrfs@vger.kernel.org, David Sterba , "Darrick J . Wong" , 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 Subject: Re: [PATCH V10 12/19] block: allow bio_for_each_segment_all() to iterate over multi-page bvec Message-ID: <20181119083218.GH16736@ming.t460p> References: <20181115085306.9910-1-ming.lei@redhat.com> <20181115085306.9910-13-ming.lei@redhat.com> <20181116012245.GG23828@vader> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181116012245.GG23828@vader> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Nov 15, 2018 at 05:22:45PM -0800, Omar Sandoval wrote: > On Thu, Nov 15, 2018 at 04:52:59PM +0800, Ming Lei wrote: > > This patch introduces one extra iterator variable to bio_for_each_segment_all(), > > then we can allow bio_for_each_segment_all() to iterate over multi-page bvec. > > > > Given it is just one mechannical & simple change on all bio_for_each_segment_all() > > users, this patch does tree-wide change in one single patch, so that we can > > avoid to use a temporary helper for this conversion. > > > > Cc: Dave Chinner > > Cc: Kent Overstreet > > Cc: linux-fsdevel@vger.kernel.org > > Cc: Alexander Viro > > Cc: Shaohua Li > > Cc: linux-raid@vger.kernel.org > > Cc: linux-erofs@lists.ozlabs.org > > Cc: linux-btrfs@vger.kernel.org > > Cc: David Sterba > > Cc: Darrick J. Wong > > 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 > > Signed-off-by: Ming Lei > > --- > > block/bio.c | 27 ++++++++++++++++++--------- > > block/blk-zoned.c | 1 + > > block/bounce.c | 6 ++++-- > > drivers/md/bcache/btree.c | 3 ++- > > drivers/md/dm-crypt.c | 3 ++- > > drivers/md/raid1.c | 3 ++- > > drivers/staging/erofs/data.c | 3 ++- > > drivers/staging/erofs/unzip_vle.c | 3 ++- > > fs/block_dev.c | 6 ++++-- > > fs/btrfs/compression.c | 3 ++- > > fs/btrfs/disk-io.c | 3 ++- > > fs/btrfs/extent_io.c | 12 ++++++++---- > > fs/btrfs/inode.c | 6 ++++-- > > fs/btrfs/raid56.c | 3 ++- > > fs/crypto/bio.c | 3 ++- > > fs/direct-io.c | 4 +++- > > fs/exofs/ore.c | 3 ++- > > fs/exofs/ore_raid.c | 3 ++- > > fs/ext4/page-io.c | 3 ++- > > fs/ext4/readpage.c | 3 ++- > > fs/f2fs/data.c | 9 ++++++--- > > fs/gfs2/lops.c | 6 ++++-- > > fs/gfs2/meta_io.c | 3 ++- > > fs/iomap.c | 6 ++++-- > > fs/mpage.c | 3 ++- > > fs/xfs/xfs_aops.c | 5 +++-- > > include/linux/bio.h | 11 +++++++++-- > > include/linux/bvec.h | 31 +++++++++++++++++++++++++++++++ > > 28 files changed, 129 insertions(+), 46 deletions(-) > > > > [snip] > > > diff --git a/include/linux/bio.h b/include/linux/bio.h > > index 3496c816946e..1a2430a8b89d 100644 > > --- a/include/linux/bio.h > > +++ b/include/linux/bio.h > > @@ -131,12 +131,19 @@ static inline bool bio_full(struct bio *bio) > > return bio->bi_vcnt >= bio->bi_max_vecs; > > } > > > > +#define bvec_for_each_segment(bv, bvl, i, iter_all) \ > > + for (bv = bvec_init_iter_all(&iter_all); \ > > + (iter_all.done < (bvl)->bv_len) && \ > > + ((bvec_next_segment((bvl), &iter_all)), 1); \ > > The parentheses around (bvec_next_segment((bvl), &iter_all)) are > unnecessary. OK. > > > + iter_all.done += bv->bv_len, i += 1) > > + > > /* > > * drivers should _never_ use the all version - the bio may have been split > > * before it got to the driver and the driver won't own all of it > > */ > > -#define bio_for_each_segment_all(bvl, bio, i) \ > > - for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++) > > +#define bio_for_each_segment_all(bvl, bio, i, iter_all) \ > > + for (i = 0, iter_all.idx = 0; iter_all.idx < (bio)->bi_vcnt; iter_all.idx++) \ > > + bvec_for_each_segment(bvl, &((bio)->bi_io_vec[iter_all.idx]), i, iter_all) > > Would it be possible to move i into iter_all to streamline this a bit? That may may cause unnecessary conversion work for us, because the local variable 'i' is defined in external function. > > > static inline void __bio_advance_iter(struct bio *bio, struct bvec_iter *iter, > > unsigned bytes, bool mp) > > diff --git a/include/linux/bvec.h b/include/linux/bvec.h > > index 01616a0b6220..02f26d2b59ad 100644 > > --- a/include/linux/bvec.h > > +++ b/include/linux/bvec.h > > @@ -82,6 +82,12 @@ struct bvec_iter { > > current bvec */ > > }; > > > > +struct bvec_iter_all { > > + struct bio_vec bv; > > + int idx; > > + unsigned done; > > +}; > > + > > /* > > * various member access, note that bio_data should of course not be used > > * on highmem page vectors > > @@ -216,6 +222,31 @@ static inline bool mp_bvec_iter_advance(const struct bio_vec *bv, > > .bi_bvec_done = 0, \ > > } > > > > +static inline struct bio_vec *bvec_init_iter_all(struct bvec_iter_all *iter_all) > > +{ > > + iter_all->bv.bv_page = NULL; > > + iter_all->done = 0; > > + > > + return &iter_all->bv; > > +} > > + > > +/* used for chunk_for_each_segment */ > > +static inline void bvec_next_segment(const struct bio_vec *bvec, > > + struct bvec_iter_all *iter_all) > > Indentation. OK. > > > +{ > > + struct bio_vec *bv = &iter_all->bv; > > + > > + if (bv->bv_page) { > > + bv->bv_page += 1; > > + bv->bv_offset = 0; > > + } else { > > + bv->bv_page = bvec->bv_page; > > + bv->bv_offset = bvec->bv_offset; > > + } > > + bv->bv_len = min_t(unsigned int, PAGE_SIZE - bv->bv_offset, > > + bvec->bv_len - iter_all->done); > > Indentation. OK. -- Ming