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: 57+ 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]
2018-06-11 16:48 ` [PATCH V6 00/30] block: support multipage bvec Christoph Hellwig
2018-06-12 3:42 ` Ming Lei
2018-06-13 14:42 ` Christoph Hellwig
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
2018-06-21 1:17 ` Ming Lei
2018-06-21 8:40 ` Gi-Oh Kim
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