Introduce rq_for_each_segment replacing rq_for_each_bio

Every usage of rq_for_each_bio wraps a usage of
bio_for_each_segment, so these can be combined into
rq_for_each_segment.

We define "struct req_iterator" to hold the 'bio' and 'index' that
are needed for the double iteration.

Signed-off-by: Neil Brown <neilb@suse.de>

Various compile fixes by me...

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 2 insertions, 5 deletions

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 964e51634f2d..6af250113c2a 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -150,9 +150,8 @@ static int blkif_queue_request(struct request *req)
         struct blkfront_info *info = req->rq_disk->private_data;
         unsigned long buffer_mfn;
         struct blkif_request *ring_req;
-        struct bio *bio;
+        struct req_iterator iter;
         struct bio_vec *bvec;
-        int idx;
         unsigned long id;
         unsigned int fsect, lsect;
         int ref;
@@ -186,8 +185,7 @@ static int blkif_queue_request(struct request *req)
                 ring_req->operation = BLKIF_OP_WRITE_BARRIER;
 
         ring_req->nr_segments = 0;
-        rq_for_each_bio (bio, req) {
-                bio_for_each_segment (bvec, bio, idx) {
+        rq_for_each_segment(bvec, req, iter) {
                         BUG_ON(ring_req->nr_segments
                                == BLKIF_MAX_SEGMENTS_PER_REQUEST);
                         buffer_mfn = pfn_to_mfn(page_to_pfn(bvec->bv_page));
@@ -213,7 +211,6 @@ static int blkif_queue_request(struct request *req)
                                         .last_sect  = lsect };
 
                         ring_req->nr_segments++;
-                }
         }
 
         info->ring.req_prod_pvt++;