block: fix bogus compiler warnings in blk-merge.c

The compiler can't figure out that bvprv is initialized whenever 'prev'
is set to 1 as well. Use a pointer to bvprv instead, setting it to NULL
initially, and get rid of the 'prev' tracking. This dumbs it down
enough that gcc is happy.

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

diff --git a/block/blk-merge.c b/block/blk-merge.c
index d088cffb810508a5e55f7543bc134537329d00ec..cce23ba1ae5fdd29c936454f11981c818228829c 100644 (file)
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -67,10 +67,9 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
                                         struct bio_set *bs)
 {
        struct bio *split;
-       struct bio_vec bv, bvprv;
+       struct bio_vec bv, bvprv, *bvprvp = NULL;
        struct bvec_iter iter;
        unsigned seg_size = 0, nsegs = 0, sectors = 0;
-       int prev = 0;
 
        bio_for_each_segment(bv, bio, iter) {
                sectors += bv.bv_len >> 9;
@@ -82,20 +81,20 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
                 * If the queue doesn't support SG gaps and adding this
                 * offset would create a gap, disallow it.
                 */
-               if (prev && bvec_gap_to_prev(q, &bvprv, bv.bv_offset))
+               if (bvprvp && bvec_gap_to_prev(q, bvprvp, bv.bv_offset))
                        goto split;
 
-               if (prev && blk_queue_cluster(q)) {
+               if (bvprvp && blk_queue_cluster(q)) {
                        if (seg_size + bv.bv_len > queue_max_segment_size(q))
                                goto new_segment;
-                       if (!BIOVEC_PHYS_MERGEABLE(&bvprv, &bv))
+                       if (!BIOVEC_PHYS_MERGEABLE(bvprvp, &bv))
                                goto new_segment;
-                       if (!BIOVEC_SEG_BOUNDARY(q, &bvprv, &bv))
+                       if (!BIOVEC_SEG_BOUNDARY(q, bvprvp, &bv))
                                goto new_segment;
 
                        seg_size += bv.bv_len;
                        bvprv = bv;
-                       prev = 1;
+                       bvprvp = &bv;
                        continue;
                }
 new_segment:
@@ -104,7 +103,7 @@ new_segment:
 
                nsegs++;
                bvprv = bv;
-               prev = 1;
+               bvprvp = &bv;
                seg_size = bv.bv_len;
        }