Messages in this thread | | | Date | Thu, 20 Sep 2012 17:50:35 -0700 | From | Kent Overstreet <> | Subject | Re: [PATCH v2 21/26] block: Convert some code to bio_for_each_segment_all() |
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On Thu, Sep 20, 2012 at 05:38:32PM -0700, Tejun Heo wrote: > On Mon, Sep 10, 2012 at 05:22:32PM -0700, Kent Overstreet wrote: > > A few places in the code were either open coding or using the wrong > > version - fix. > > > > Signed-off-by: Kent Overstreet <koverstreet@google.com> > > CC: Jens Axboe <axboe@kernel.dk> > > CC: NeilBrown <neilb@suse.de> > > --- > > --- a/drivers/md/raid1.c > > +++ b/drivers/md/raid1.c > > @@ -921,7 +921,7 @@ static void alloc_behind_pages(struct bio *bio, struct r1bio *r1_bio) > > if (unlikely(!bvecs)) > > return; > > > > - bio_for_each_segment(bvec, bio, i) { > > + bio_for_each_segment_all(bvec, bio, i) { > > I don't get this conversion. Why is this necessary?
Not necessary, just a consistency thing - this bio is a clone that md owns (and the clone was trimmed, so we know bi_idx is 0).
Also, it wasn't an issue here but after the patch that introduces the bvec iter it's no longer possible to modify the biovec through bio_for_each_segment_all() - it doesn't increment a pointer to the current bvec, you pass in a struct bio_vec (not a pointer) which is updated with what the current biovec would be (taking into account bi_bvec_done and bi_size).
So because of that it is IMO more worthwhile to be consistent about bio_for_each_segment()/bio_for_each_segment_all() usage.
Suppose I should stick all that in the patch description.
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