block: fix missing bio back/front segment size setting in blk_recount_segments()

Commit 1e42807918d17e8c93bf14fbb74be84b141334c1 introduced a bug where we
don't get front/back segment sizes in the bio in blk_recount_segments().
Fix this by tracking the back bio as well as the front bio in
__blk_recalc_rq_segments(), this also cleans up the interface by getting
rid of the segment size pointer passing.

Tested-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/block/blk-merge.c b/block/blk-merge.c
index a104593e70c38cdfdaebc1cf1214934e37ce3284..5a244f05360f5ca67592e29a7270f3874bf16c37 100644 (file)
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -39,14 +39,13 @@ void blk_recalc_rq_sectors(struct request *rq, int nsect)
 }
 
 static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
-                                            struct bio *bio,
-                                            unsigned int *seg_size_ptr)
+                                            struct bio *bio)
 {
        unsigned int phys_size;
        struct bio_vec *bv, *bvprv = NULL;
        int cluster, i, high, highprv = 1;
        unsigned int seg_size, nr_phys_segs;
-       struct bio *fbio;
+       struct bio *fbio, *bbio;
 
        if (!bio)
                return 0;
@@ -87,26 +86,20 @@ new_segment:
                        seg_size = bv->bv_len;
                        highprv = high;
                }
+               bbio = bio;
        }
 
-       if (seg_size_ptr)
-               *seg_size_ptr = seg_size;
+       if (nr_phys_segs == 1 && seg_size > fbio->bi_seg_front_size)
+               fbio->bi_seg_front_size = seg_size;
+       if (seg_size > bbio->bi_seg_back_size)
+               bbio->bi_seg_back_size = seg_size;
 
        return nr_phys_segs;
 }
 
 void blk_recalc_rq_segments(struct request *rq)
 {
-       unsigned int seg_size = 0, phys_segs;
-
-       phys_segs = __blk_recalc_rq_segments(rq->q, rq->bio, &seg_size);
-
-       if (phys_segs == 1 && seg_size > rq->bio->bi_seg_front_size)
-               rq->bio->bi_seg_front_size = seg_size;
-       if (seg_size > rq->biotail->bi_seg_back_size)
-               rq->biotail->bi_seg_back_size = seg_size;
-
-       rq->nr_phys_segments = phys_segs;
+       rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio);
 }
 
 void blk_recount_segments(struct request_queue *q, struct bio *bio)
@@ -114,7 +107,7 @@ void blk_recount_segments(struct request_queue *q, struct bio *bio)
        struct bio *nxt = bio->bi_next;
 
        bio->bi_next = NULL;
-       bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, NULL);
+       bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio);
        bio->bi_next = nxt;
        bio->bi_flags |= (1 << BIO_SEG_VALID);
 }