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, 6 insertions, 13 deletions

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index e35119a72a44..094c0fa5c405 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -1244,8 +1244,7 @@ static void blk_recalc_rq_segments(struct request *rq)
         int seg_size;
         int hw_seg_size;
         int cluster;
-        struct bio *bio;
-        int i;
+        struct req_iterator iter;
         int high, highprv = 1;
         struct request_queue *q = rq->q;
 
@@ -1255,8 +1254,7 @@ static void blk_recalc_rq_segments(struct request *rq)
         cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER);
         hw_seg_size = seg_size = 0;
         phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0;
-        rq_for_each_bio(bio, rq)
-            bio_for_each_segment(bv, bio, i) {
+        rq_for_each_segment(bv, rq, iter) {
                 /*
                  * the trick here is making sure that a high page is never
                  * considered part of another segment, since that might
@@ -1353,8 +1351,8 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
                   struct scatterlist *sg)
 {
         struct bio_vec *bvec, *bvprv;
-        struct bio *bio;
-        int nsegs, i, cluster;
+        struct req_iterator iter;
+        int nsegs, cluster;
 
         nsegs = 0;
         cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER);
@@ -1363,11 +1361,7 @@ int blk_rq_map_sg(struct request_queue *q, struct request *rq,
          * for each bio in rq
          */
         bvprv = NULL;
-        rq_for_each_bio(bio, rq) {
-                /*
-                 * for each segment in bio
-                 */
-                bio_for_each_segment(bvec, bio, i) {
+        rq_for_each_segment(bvec, rq, iter) {
                         int nbytes = bvec->bv_len;
 
                         if (bvprv && cluster) {
@@ -1390,8 +1384,7 @@ new_segment:
                                 nsegs++;
                         }
                         bvprv = bvec;
-                } /* segments in bio */
-        } /* bios in rq */
+        } /* segments in rq */
 
         return nsegs;
 }