There are still cases in which we need to use bio_bvecs() for get the
number of multi-page segment, so introduce it.

Cc: Dave Chinner <dchin...@redhat.com>
Cc: Kent Overstreet <kent.overstr...@gmail.com>
Cc: Mike Snitzer <snit...@redhat.com>
Cc: dm-devel@redhat.com
Cc: Alexander Viro <v...@zeniv.linux.org.uk>
Cc: linux-fsde...@vger.kernel.org
Cc: Shaohua Li <s...@kernel.org>
Cc: linux-r...@vger.kernel.org
Cc: linux-er...@lists.ozlabs.org
Cc: David Sterba <dste...@suse.com>
Cc: linux-bt...@vger.kernel.org
Cc: Darrick J. Wong <darrick.w...@oracle.com>
Cc: linux-...@vger.kernel.org
Cc: Gao Xiang <gaoxian...@huawei.com>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Theodore Ts'o <ty...@mit.edu>
Cc: linux-e...@vger.kernel.org
Cc: Coly Li <col...@suse.de>
Cc: linux-bca...@vger.kernel.org
Cc: Boaz Harrosh <o...@electrozaur.com>
Cc: Bob Peterson <rpete...@redhat.com>
Cc: cluster-de...@redhat.com
Signed-off-by: Ming Lei <ming....@redhat.com>
---
 include/linux/bio.h | 30 +++++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/include/linux/bio.h b/include/linux/bio.h
index 1f0dcf109841..3496c816946e 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -196,7 +196,6 @@ static inline unsigned bio_segments(struct bio *bio)
         * We special case discard/write same/write zeroes, because they
         * interpret bi_size differently:
         */
-
        switch (bio_op(bio)) {
        case REQ_OP_DISCARD:
        case REQ_OP_SECURE_ERASE:
@@ -205,13 +204,34 @@ static inline unsigned bio_segments(struct bio *bio)
        case REQ_OP_WRITE_SAME:
                return 1;
        default:
-               break;
+               bio_for_each_segment(bv, bio, iter)
+                       segs++;
+               return segs;
        }
+}
 
-       bio_for_each_segment(bv, bio, iter)
-               segs++;
+static inline unsigned bio_bvecs(struct bio *bio)
+{
+       unsigned bvecs = 0;
+       struct bio_vec bv;
+       struct bvec_iter iter;
 
-       return segs;
+       /*
+        * We special case discard/write same/write zeroes, because they
+        * interpret bi_size differently:
+        */
+       switch (bio_op(bio)) {
+       case REQ_OP_DISCARD:
+       case REQ_OP_SECURE_ERASE:
+       case REQ_OP_WRITE_ZEROES:
+               return 0;
+       case REQ_OP_WRITE_SAME:
+               return 1;
+       default:
+               bio_for_each_bvec(bv, bio, iter)
+                       bvecs++;
+               return bvecs;
+       }
 }
 
 /*
-- 
2.9.5

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