block: ensure to split after potentially bouncing a bio

blk_queue_bio() does split then bounce, which makes the segment
counting based on pages before bouncing and could go wrong. Move
the split to after bouncing, like we do for blk-mq, and the we
fix the issue of having the bio count for segments be wrong.

Fixes: 54efd50bfd87 ("block: make generic_make_request handle arbitrarily sized bios")
Cc: stable@vger.kernel.org
Tested-by: Artem S. Tashkinov <t.artem@lycos.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-core.c b/block/blk-core.c
index 3636be469fa2edfef939985135654a394d639a9b..c487b94c59e3052074f5e40c99680d0cb709b517 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1689,8 +1689,6 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
        struct request *req;
        unsigned int request_count = 0;
 
-       blk_queue_split(q, &bio, q->bio_split);
-
        /*
         * low level driver can indicate that it wants pages above a
         * certain limit bounced to low memory (ie for highmem, or even
@@ -1698,6 +1696,8 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
         */
        blk_queue_bounce(q, &bio);
 
+       blk_queue_split(q, &bio, q->bio_split);
+
        if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
                bio->bi_error = -EIO;
                bio_endio(bio);