| Message ID | 20181126021720.19471-19-ming.lei@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: support multi-page bvec | expand |
On Mon, Nov 26, 2018 at 10:17:18AM +0800, Ming Lei wrote: > Now multi-page bvec is supported, some helpers may return page by > page, meantime some may return segment by segment, this patch > documents the usage. > > Signed-off-by: Ming Lei <ming.lei@redhat.com> Looks fine, Reviewed-by: Christoph Hellwig <hch@lst.de>
On Mon, Nov 26, 2018 at 10:17:18AM +0800, Ming Lei wrote: > Now multi-page bvec is supported, some helpers may return page by > page, meantime some may return segment by segment, this patch > documents the usage. Reviewed-by: Omar Sandoval <osandov@fb.com> > Signed-off-by: Ming Lei <ming.lei@redhat.com> > --- > Documentation/block/biovecs.txt | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/Documentation/block/biovecs.txt b/Documentation/block/biovecs.txt > index 25689584e6e0..ce6eccaf5df7 100644 > --- a/Documentation/block/biovecs.txt > +++ b/Documentation/block/biovecs.txt > @@ -117,3 +117,28 @@ 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 of "_all" can only be used > +on non-BIO_CLONED bio. They are usually used by filesystem code. Drivers > +shouldn't use them because the bio may have been split before it reached the > +driver. > + > + bio_for_each_segment_all() > + bio_first_bvec_all() > + bio_first_page_all() > + bio_last_bvec_all() > + > +* The following helpers iterate over single-page segment. The passed 'struct > +bio_vec' will contain a single-page IO vector during the iteration > + > + bio_for_each_segment() > + bio_for_each_segment_all() > + > +* The following helpers iterate over multi-page bvec. The passed 'struct > +bio_vec' will contain a multi-page IO vector during the iteration > + > + bio_for_each_bvec() > + rq_for_each_bvec() > -- > 2.9.5 >
diff --git a/Documentation/block/biovecs.txt b/Documentation/block/biovecs.txt index 25689584e6e0..ce6eccaf5df7 100644 --- a/Documentation/block/biovecs.txt +++ b/Documentation/block/biovecs.txt @@ -117,3 +117,28 @@ 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 of "_all" can only be used +on non-BIO_CLONED bio. They are usually used by filesystem code. Drivers +shouldn't use them because the bio may have been split before it reached the +driver. + + bio_for_each_segment_all() + bio_first_bvec_all() + bio_first_page_all() + bio_last_bvec_all() + +* The following helpers iterate over single-page segment. The passed 'struct +bio_vec' will contain a single-page IO vector during the iteration + + bio_for_each_segment() + bio_for_each_segment_all() + +* The following helpers iterate over multi-page bvec. The passed 'struct +bio_vec' will contain a multi-page IO vector during the iteration + + bio_for_each_bvec() + rq_for_each_bvec()
Now multi-page bvec is supported, some helpers may return page by page, meantime some may return segment by segment, this patch documents the usage. Signed-off-by: Ming Lei <ming.lei@redhat.com> --- Documentation/block/biovecs.txt | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+)