dm crypt: leverage immutable biovecs when decrypting on read

Commit 003b5c571 ("block: Convert drivers to immutable biovecs")
stopped short of changing dm-crypt to leverage the fact that the biovec
array of a bio will no longer be modified.

Switch to using bio_clone_fast() when cloning bios for decryption after
read.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index ea09d5464a9f..aa1238facbeb 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1124,15 +1124,15 @@ static void clone_init(struct dm_crypt_io *io, struct bio *clone)
 static int kcryptd_io_read(struct dm_crypt_io *io, gfp_t gfp)
 {
         struct crypt_config *cc = io->cc;
-        struct bio *base_bio = io->base_bio;
         struct bio *clone;
 
         /*
-         * The block layer might modify the bvec array, so always
-         * copy the required bvecs because we need the original
-         * one in order to decrypt the whole bio data *afterwards*.
+         * We need the original biovec array in order to decrypt
+         * the whole bio data *afterwards* -- thanks to immutable
+         * biovecs we don't need to worry about the block layer
+         * modifying the biovec array; so leverage bio_clone_fast().
          */
-        clone = bio_clone_bioset(base_bio, gfp, cc->bs);
+        clone = bio_clone_fast(io->base_bio, gfp, cc->bs);
         if (!clone)
                 return 1;