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>
This commit is contained in:
Mike Snitzer 2015-04-09 16:53:24 -04:00
parent e44f23b32d
commit 5977907937

View File

@ -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;