__bio_clone: don't calculate hw/phys segment counts

If the users sets a new ->bi_bdev on the bio after __bio_clone() has
returned it, the "segment counts valid" flag still remains even though
it may be different with the new target. So don't calculate segment
counts in __bio_clone().

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

1 files changed, 4 insertions, 4 deletions

diff --git a/fs/bio.c b/fs/bio.c
index d59ddbf79626..242e409dab4b 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -248,11 +248,13 @@ inline int bio_hw_segments(struct request_queue *q, struct bio *bio)
  */
 void __bio_clone(struct bio *bio, struct bio *bio_src)
 {
-        struct request_queue *q = bdev_get_queue(bio_src->bi_bdev);
-
         memcpy(bio->bi_io_vec, bio_src->bi_io_vec,
                 bio_src->bi_max_vecs * sizeof(struct bio_vec));
 
+        /*
+         * most users will be overriding ->bi_bdev with a new target,
+         * so we don't set nor calculate new physical/hw segment counts here
+         */
         bio->bi_sector = bio_src->bi_sector;
         bio->bi_bdev = bio_src->bi_bdev;
         bio->bi_flags |= 1 << BIO_CLONED;
@@ -260,8 +262,6 @@ void __bio_clone(struct bio *bio, struct bio *bio_src)
         bio->bi_vcnt = bio_src->bi_vcnt;
         bio->bi_size = bio_src->bi_size;
         bio->bi_idx = bio_src->bi_idx;
-        bio_phys_segments(q, bio);
-        bio_hw_segments(q, bio);
 }
 
 /**