rbd: Refactor bio cloning

Now that we've got drivers converted to the new immutable bvec
primitives, bio splitting becomes much easier - this is how the new
bio_split() will work. (Someone more familiar with the ceph code could
probably use bio_clone_fast() instead of bio_clone() here).

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Alex Elder <elder@inktank.com>
Cc: ceph-devel@vger.kernel.org

diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 20e8ab35736bbf4c03a7ecb50cadc621c204a46b..3624368b910dd30fe841cb42e2f13a8ec5109bc8 100644 (file)
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -1173,73 +1173,13 @@ static struct bio *bio_clone_range(struct bio *bio_src,
                                        unsigned int len,
                                        gfp_t gfpmask)
 {
-       struct bio_vec bv;
-       struct bvec_iter iter;
-       struct bvec_iter end_iter;
-       unsigned int resid;
-       unsigned int voff;
-       unsigned short vcnt;
        struct bio *bio;
 
-       /* Handle the easy case for the caller */
-
-       if (!offset && len == bio_src->bi_iter.bi_size)
-               return bio_clone(bio_src, gfpmask);
-
-       if (WARN_ON_ONCE(!len))
-               return NULL;
-       if (WARN_ON_ONCE(len > bio_src->bi_iter.bi_size))
-               return NULL;
-       if (WARN_ON_ONCE(offset > bio_src->bi_iter.bi_size - len))
-               return NULL;
-
-       /* Find first affected segment... */
-
-       resid = offset;
-       bio_for_each_segment(bv, bio_src, iter) {
-               if (resid < bv.bv_len)
-                       break;
-               resid -= bv.bv_len;
-       }
-       voff = resid;
-
-       /* ...and the last affected segment */
-
-       resid += len;
-       __bio_for_each_segment(bv, bio_src, end_iter, iter) {
-               if (resid <= bv.bv_len)
-                       break;
-               resid -= bv.bv_len;
-       }
-       vcnt = end_iter.bi_idx = iter.bi_idx + 1;
-
-       /* Build the clone */
-
-       bio = bio_alloc(gfpmask, (unsigned int) vcnt);
+       bio = bio_clone(bio_src, gfpmask);
        if (!bio)
                return NULL;    /* ENOMEM */
 
-       bio->bi_bdev = bio_src->bi_bdev;
-       bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector +
-               (offset >> SECTOR_SHIFT);
-       bio->bi_rw = bio_src->bi_rw;
-       bio->bi_flags |= 1 << BIO_CLONED;
-
-       /*
-        * Copy over our part of the bio_vec, then update the first
-        * and last (or only) entries.
-        */
-       memcpy(&bio->bi_io_vec[0], &bio_src->bi_io_vec[iter.bi_idx],
-                       vcnt * sizeof (struct bio_vec));
-       bio->bi_io_vec[0].bv_offset += voff;
-       if (vcnt > 1) {
-               bio->bi_io_vec[0].bv_len -= voff;
-               bio->bi_io_vec[vcnt - 1].bv_len = resid;
-       } else {
-               bio->bi_io_vec[0].bv_len = len;
-       }
-
-       bio->bi_vcnt = vcnt;
+       bio_advance(bio, offset);
        bio->bi_iter.bi_size = len;
 
        return bio;