On Mon, Oct 31, 2016 at 9:59 PM, Theodore Ts'o [off-list ref] wrote:

On Sat, Oct 29, 2016 at 04:08:44PM +0800, Ming Lei wrote:

quoted

This patches introduce bio_for_each_segment_all_rd() and
bio_for_each_segment_all_wt().

bio_for_each_segment_all_rd() is for replacing
bio_for_each_segment_all() in case the bvec from bio->bi_io_vec
is accessed as readonly.

bio_for_each_segment_all_wt() is for replacing
bio_for_each_segment_all() in case the bvec from bio->bi_io_vec
need to be updated.

What is _rd and _wt supposed to stand for?  And speaking more

As Christoph replied, _rd means read, which said the bvec pointed by
the iterator variable(bvec pointer) is read-only, and the bvec table
can't be written into via this usage any more. Maybe
bio_for_each_segment_all_ro is better?

On the other hand, _wr meands write, which said the bvec pointed by
the iterator variable(bvec pointer) can be written to. Maybe we can use
original bio_for_each_segment_all() for it?

generally, could you write up some more detailed notes about all of
the various new functions they have been added, when they should be
used, and some kind of roadmap about how things are supposed to work
beyond the very high-level description in the introduction in your
patch series?  Ideally it would go into the Documentation directory,
so that after this patch set gets applied, people will be able to
refer to it to understand how things are supposed to work.

In the next post, I will add comment on the two helpers, thanks for
your review.

Thanks,
Ming

Thanks!!

                                                - Ted

-- 
Ming Lei