From: Gi-Oh Kim <gi-oh.kim@profitbricks.com> To: ming.lei@redhat.com Cc: Jens Axboe <axboe@fb.com>, hch@infradead.org, Al Viro <viro@zeniv.linux.org.uk>, kent.overstreet@gmail.com, dsterba@suse.cz, ying.huang@intel.com, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, tytso@mit.edu, darrick.wong@oracle.com, colyli@suse.de, fdmanana@gmail.com, rdunlap@infradead.org Subject: Re: [PATCH V6 30/30] block: document usage of bio iterator helpers Date: Fri, 15 Jun 2018 17:43:22 +0200 [thread overview] Message-ID: <CAJX1YtZYrRwQgASEX_CQtBEcYuk02LA=cKibsx=TitC70_=+zg@mail.gmail.com> (raw) In-Reply-To: <20180609123014.8861-31-ming.lei@redhat.com> On Sat, Jun 9, 2018 at 2:36 PM Ming Lei <ming.lei@redhat.com> wrote: > > Now multipage bvec is supported, and some helpers may return page by > page, and some may return segment by segment, this patch documents the > usage for helping us use them correctly. > > Signed-off-by: Ming Lei <ming.lei@redhat.com> > --- > Documentation/block/biovecs.txt | 30 ++++++++++++++++++++++++++++++ > 1 file changed, 30 insertions(+) > > diff --git a/Documentation/block/biovecs.txt b/Documentation/block/biovec= s.txt > index 25689584e6e0..3ab72566141f 100644 > --- a/Documentation/block/biovecs.txt > +++ b/Documentation/block/biovecs.txt > @@ -117,3 +117,33 @@ Other implications: > size limitations and the limitations of the underlying devices. Thus > there's no need to define ->merge_bvec_fn() callbacks for individual = block > drivers. > + > +Usage of helpers: > +=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > + > +* The following helpers, whose names have the suffix "_all", can only be > +used on non-BIO_CLONED bio, and usually they are used by filesystem code= , > +and driver shouldn't use them because bio may have been split before the= y > +got to the driver: > + > + bio_for_each_chunk_segment_all() > + bio_for_each_chunk_all() > + bio_pages_all() > + bio_first_bvec_all() > + bio_first_page_all() > + bio_last_bvec_all() > + > +* The following helpers iterate bio page by page, and the local variable= of > +'struct bio_vec' or the reference records single page io vector during t= he > +iteration: > + > + bio_for_each_segment() > + bio_for_each_segment_all() bio_for_each_segment_all() is removed, isn't it? > + > +* The following helpers iterate bio chunk by chunk, and each chunk may > +include multiple physically contiguous pages, and the local variable of > +'struct bio_vec' or the reference records multi page io vector during th= e > +iteration: > + > + bio_for_each_chunk() > + bio_for_each_chunk_all() > -- > 2.9.5 > --=20 GIOH KIM Linux Kernel Entwickler ProfitBricks GmbH Greifswalder Str. 207 D - 10405 Berlin Tel: +49 176 2697 8962 Fax: +49 30 577 008 299 Email: gi-oh.kim@profitbricks.com URL: https://www.profitbricks.de Sitz der Gesellschaft: Berlin Registergericht: Amtsgericht Charlottenburg, HRB 125506 B Gesch=C3=A4ftsf=C3=BChrer: Achim Weiss, Matthias Steinberg, Christoph Steff= ens
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From: Gi-Oh Kim <gi-oh.kim@profitbricks.com> To: ming.lei@redhat.com Cc: Jens Axboe <axboe@fb.com>, hch@infradead.org, Al Viro <viro@zeniv.linux.org.uk>, kent.overstreet@gmail.com, dsterba@suse.cz, ying.huang@intel.com, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, tytso@mit.edu, darrick.wong@oracle.com, colyli@suse.de, fdmanana@gmail.com, rdunlap@infradead.org Subject: Re: [PATCH V6 30/30] block: document usage of bio iterator helpers Date: Fri, 15 Jun 2018 17:43:22 +0200 [thread overview] Message-ID: <CAJX1YtZYrRwQgASEX_CQtBEcYuk02LA=cKibsx=TitC70_=+zg@mail.gmail.com> (raw) In-Reply-To: <20180609123014.8861-31-ming.lei@redhat.com> On Sat, Jun 9, 2018 at 2:36 PM Ming Lei <ming.lei@redhat.com> wrote: > > Now multipage bvec is supported, and some helpers may return page by > page, and some may return segment by segment, this patch documents the > usage for helping us use them correctly. > > Signed-off-by: Ming Lei <ming.lei@redhat.com> > --- > Documentation/block/biovecs.txt | 30 ++++++++++++++++++++++++++++++ > 1 file changed, 30 insertions(+) > > diff --git a/Documentation/block/biovecs.txt b/Documentation/block/biovecs.txt > index 25689584e6e0..3ab72566141f 100644 > --- a/Documentation/block/biovecs.txt > +++ b/Documentation/block/biovecs.txt > @@ -117,3 +117,33 @@ Other implications: > size limitations and the limitations of the underlying devices. Thus > there's no need to define ->merge_bvec_fn() callbacks for individual block > drivers. > + > +Usage of helpers: > +================= > + > +* The following helpers, whose names have the suffix "_all", can only be > +used on non-BIO_CLONED bio, and usually they are used by filesystem code, > +and driver shouldn't use them because bio may have been split before they > +got to the driver: > + > + bio_for_each_chunk_segment_all() > + bio_for_each_chunk_all() > + bio_pages_all() > + bio_first_bvec_all() > + bio_first_page_all() > + bio_last_bvec_all() > + > +* The following helpers iterate bio page by page, and the local variable of > +'struct bio_vec' or the reference records single page io vector during the > +iteration: > + > + bio_for_each_segment() > + bio_for_each_segment_all() bio_for_each_segment_all() is removed, isn't it? > + > +* The following helpers iterate bio chunk by chunk, and each chunk may > +include multiple physically contiguous pages, and the local variable of > +'struct bio_vec' or the reference records multi page io vector during the > +iteration: > + > + bio_for_each_chunk() > + bio_for_each_chunk_all() > -- > 2.9.5 > -- GIOH KIM Linux Kernel Entwickler ProfitBricks GmbH Greifswalder Str. 207 D - 10405 Berlin Tel: +49 176 2697 8962 Fax: +49 30 577 008 299 Email: gi-oh.kim@profitbricks.com URL: https://www.profitbricks.de Sitz der Gesellschaft: Berlin Registergericht: Amtsgericht Charlottenburg, HRB 125506 B Geschäftsführer: Achim Weiss, Matthias Steinberg, Christoph Steffens
next prev parent reply other threads:[~2018-06-15 15:43 UTC|newest] Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-06-09 12:29 [PATCH V6 00/30] block: support multipage bvec Ming Lei 2018-06-09 12:29 ` [PATCH V6 01/30] block: simplify bio_check_pages_dirty Ming Lei 2018-06-09 12:29 ` [PATCH V6 02/30] block: bio_set_pages_dirty can't see NULL bv_page in a valid bio_vec Ming Lei 2018-06-09 12:29 ` [PATCH V6 03/30] block: use bio_add_page in bio_iov_iter_get_pages Ming Lei 2018-06-09 12:29 ` [PATCH V6 04/30] block: introduce multipage page bvec helpers Ming Lei 2018-06-09 12:29 ` [PATCH V6 05/30] block: introduce bio_for_each_chunk() Ming Lei 2018-06-09 12:29 ` [PATCH V6 06/30] block: use bio_for_each_chunk() to compute multipage bvec count Ming Lei 2018-06-09 12:29 ` [PATCH V6 07/30] block: use bio_for_each_chunk() to map sg Ming Lei 2018-06-09 12:29 ` [PATCH V6 08/30] block: introduce chunk_last_segment() Ming Lei 2018-06-11 17:19 ` Christoph Hellwig 2018-06-12 3:24 ` Ming Lei 2018-06-09 12:29 ` [PATCH V6 09/30] fs/buffer.c: use bvec iterator to truncate the bio Ming Lei 2018-06-09 12:29 ` [PATCH V6 10/30] btrfs: use chunk_last_segment to get bio's last page Ming Lei 2018-06-09 12:29 ` [PATCH V6 11/30] block: implement bio_pages_all() via bio_for_each_segment_all() Ming Lei 2018-06-13 14:44 ` Christoph Hellwig 2018-06-14 1:23 ` Ming Lei 2018-06-14 6:20 ` Christoph Hellwig 2018-06-09 12:29 ` [PATCH V6 12/30] block: introduce bio_chunks() Ming Lei 2018-06-13 14:47 ` Christoph Hellwig 2018-06-13 14:57 ` Kent Overstreet 2018-06-09 12:29 ` [PATCH V6 13/30] block: introduce rq_for_each_chunk() Ming Lei 2018-06-13 14:48 ` Christoph Hellwig 2018-06-14 1:52 ` Ming Lei 2018-06-09 12:29 ` [PATCH V6 14/30] block: loop: pass multipage chunks to iov_iter Ming Lei 2018-06-09 12:29 ` [PATCH V6 15/30] block: introduce bio_clone_chunk_bioset() Ming Lei 2018-06-13 14:56 ` Christoph Hellwig 2018-06-14 2:01 ` Ming Lei 2018-06-14 6:39 ` Christoph Hellwig 2018-06-14 7:28 ` Ming Lei 2018-06-09 12:30 ` [PATCH V6 16/30] dm: clone bio via bio_clone_chunk_bioset Ming Lei 2018-06-09 12:30 ` [PATCH V6 17/30] block: introduce bio_for_each_chunk_all and bio_for_each_chunk_segment_all Ming Lei 2018-06-09 12:30 ` [PATCH V6 18/30] block: convert to bio_for_each_chunk_segment_all() Ming Lei 2018-06-09 12:30 ` [PATCH V6 19/30] md/dm/bcache: conver to bio_for_each_chunk_segment_all and bio_for_each_chunk_all Ming Lei 2018-06-10 12:38 ` Coly Li 2018-06-13 14:57 ` Christoph Hellwig 2018-06-09 12:30 ` [PATCH V6 20/30] fs: conver to bio_for_each_chunk_segment_all() Ming Lei 2018-06-09 12:30 ` [PATCH V6 21/30] btrfs: conver to bio_for_each_chunk_segment_all Ming Lei 2018-06-09 12:30 ` [PATCH V6 22/30] ext4: " Ming Lei 2018-06-09 12:30 ` [PATCH V6 23/30] f2fs: " Ming Lei 2018-06-09 12:30 ` [PATCH V6 24/30] xfs: " Ming Lei 2018-06-09 12:30 ` [PATCH V6 25/30] exofs: " Ming Lei 2018-06-09 12:30 ` [PATCH V6 26/30] gfs2: " Ming Lei 2018-06-09 12:30 ` [PATCH V6 27/30] block: kill bio_for_each_segment_all() Ming Lei 2018-06-09 12:30 ` [PATCH V6 28/30] block: enable multipage bvecs Ming Lei 2018-06-09 12:30 ` [PATCH V6 29/30] block: always define BIO_MAX_PAGES as 256 Ming Lei 2018-06-09 12:30 ` [PATCH V6 30/30] block: document usage of bio iterator helpers Ming Lei 2018-06-15 15:43 ` Gi-Oh Kim [this message] 2018-06-15 15:43 ` Gi-Oh Kim 2018-06-11 16:48 ` [PATCH V6 00/30] block: support multipage bvec Christoph Hellwig 2018-06-11 16:48 ` Christoph Hellwig 2018-06-12 3:42 ` Ming Lei 2018-06-12 3:42 ` Ming Lei 2018-06-13 14:42 ` Christoph Hellwig 2018-06-13 14:42 ` Christoph Hellwig 2018-06-14 1:18 ` Ming Lei 2018-06-14 1:18 ` Ming Lei 2018-06-14 6:18 ` Christoph Hellwig 2018-06-13 14:59 ` Kent Overstreet 2018-06-14 1:20 ` Ming Lei 2018-06-15 12:59 ` Gi-Oh Kim 2018-06-15 12:59 ` Gi-Oh Kim 2018-06-21 1:17 ` Ming Lei 2018-06-21 8:40 ` Gi-Oh Kim 2018-06-21 8:40 ` Gi-Oh Kim
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