lkml.org 
[lkml]   [2017]   [Oct]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v3 41/49] xfs: convert to bio_for_each_segment_all_sp()
On Tue, Aug 08, 2017 at 09:32:32AM -0700, Darrick J. Wong wrote:
> On Tue, Aug 08, 2017 at 04:45:40PM +0800, Ming Lei wrote:
>
> Sure would be nice to have a changelog explaining why we're doing this.
>
> > Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
> > Cc: linux-xfs@vger.kernel.org
> > Signed-off-by: Ming Lei <ming.lei@redhat.com>
> > ---
> > fs/xfs/xfs_aops.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> > index 6bf120bb1a17..94df43dcae0b 100644
> > --- a/fs/xfs/xfs_aops.c
> > +++ b/fs/xfs/xfs_aops.c
> > @@ -139,6 +139,7 @@ xfs_destroy_ioend(
> > for (bio = &ioend->io_inline_bio; bio; bio = next) {
> > struct bio_vec *bvec;
> > int i;
> > + struct bvec_iter_all bia;
> >
> > /*
> > * For the last bio, bi_private points to the ioend, so we
> > @@ -150,7 +151,7 @@ xfs_destroy_ioend(
> > next = bio->bi_private;
> >
> > /* walk each page on bio, ending page IO on them */
> > - bio_for_each_segment_all(bvec, bio, i)
> > + bio_for_each_segment_all_sp(bvec, bio, i, bia)
>
> It's confusing that you're splitting the old bio_for_each_segment_all
> into multipage and singlepage variants, but bio_for_each_segment_all
> continues to exist?

No, it shouldn't, will remove it in V4.

>
> Hmm, the new multipage variant aliases the name bio_for_each_segment_all,
> so clearly the _all function's sematics have changed a bit, but its name
> and signature haven't, which seems likely to trip up someone who didn't
> notice the behavioral change.

bio_for_each_segment_all_mp() is introduced for providing previous
sematics of bio_for_each_segment_all(), and there is few cases in
which bvec table need to be updated.

>
> Is it still valid to call bio_for_each_segment_all? I get the feeling

No, bio_for_each_segment_all_mp() should be used instead. But my plan is
to rename bio_for_each_segment_all_mp() into bio_for_each_segment_all()
and bio_for_each_segment_all_sp() into bio_for_each_page() once this
patchset is merged.

> from this patchset that you're really supposed to decide whether you
> want one page at a time or more than one page at a time and choose _sp
> or _mp?

Yeah.

>
> (And, seeing how this was the only patch sent to this list, the chances
> are higher of someone missing out on these subtle changes...)

OK, will CC you the cover letter next time.

--
Ming

\
 
 \ /
  Last update: 2017-10-22 17:31    [W:0.069 / U:5.364 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site