On Mon, Mar 27, 2023 at 01:44:01PM -0400, Kent Overstreet wrote:
> This patch reworks bio_for_each_segment_all() to be more inline with how
> the other bio iterators work:
>
> - bio_iter_all_peek() now returns a synthesized bio_vec; we don't stash
> one in the iterator and pass a pointer to it - bad. This way makes it
> clearer what's a constructed value vs. a reference to something
> pre-existing, and it also will help with cleaning up and
> consolidating code with bio_for_each_folio_all().
>
> - We now provide bio_for_each_segment_all_continue(), for squashfs:
> this makes their code clearer.
>
> Signed-off-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
> Cc: Jens Axboe <axboe@xxxxxxxxx>
> Cc: linux-block@xxxxxxxxxxxxxxx
> Cc: Ming Lei <ming.lei@xxxxxxxxxx>
> Cc: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
> ---
> block/bio.c | 38 ++++++++++++------------
> block/blk-map.c | 38 ++++++++++++------------
> block/bounce.c | 12 ++++----
> drivers/md/bcache/btree.c | 8 ++---
> drivers/md/dm-crypt.c | 10 +++----
> drivers/md/raid1.c | 4 +--
> fs/btrfs/disk-io.c | 10 +++----
> fs/btrfs/extent_io.c | 52 ++++++++++++++++-----------------
> fs/btrfs/inode.c | 8 ++---
> fs/btrfs/raid56.c | 18 ++++++------
> fs/crypto/bio.c | 8 ++---
> fs/erofs/zdata.c | 4 +--
> fs/ext4/page-io.c | 8 ++---
> fs/ext4/readpage.c | 4 +--
> fs/f2fs/data.c | 20 ++++++-------
> fs/gfs2/lops.c | 10 +++----
> fs/gfs2/meta_io.c | 8 ++---
> fs/mpage.c | 4 +--
> fs/squashfs/block.c | 48 ++++++++++++++++--------------
> fs/squashfs/lz4_wrapper.c | 17 ++++++-----
> fs/squashfs/lzo_wrapper.c | 17 ++++++-----
> fs/verity/verify.c | 4 +--
> include/linux/bio.h | 31 +++++++++++++++-----
> include/linux/bvec.h | 61 ++++++++++++++++++++++-----------------
> 24 files changed, 239 insertions(+), 203 deletions(-)
>
> diff --git a/block/bio.c b/block/bio.c
> index ab59a491a8..8d3abe249e 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -1170,13 +1170,13 @@ bool bio_add_folio(struct bio *bio, struct folio *folio, size_t len,
>
> void __bio_release_pages(struct bio *bio, bool mark_dirty)
> {
> - struct bvec_iter_all iter_all;
> - struct bio_vec *bvec;
> + struct bvec_iter_all iter;
> + struct bio_vec bvec;
>
> - bio_for_each_segment_all(bvec, bio, iter_all) {
> - if (mark_dirty && !PageCompound(bvec->bv_page))
> - set_page_dirty_lock(bvec->bv_page);
> - put_page(bvec->bv_page);
> + bio_for_each_segment_all(bvec, bio, iter) {
> + if (mark_dirty && !PageCompound(bvec.bv_page))
> + set_page_dirty_lock(bvec.bv_page);
> + put_page(bvec.bv_page);
> }
bio_for_each_segment_all is supposed to be used by bio which owns the
bvec table, so it is just fine to return bvec pointer by bio_for_each_segment_all
to save extra bvec copy.
And the change becomes not efficient any more.
Thanks,
Ming
