dm crypt: use crypto_shash_digest() in crypt_iv_tcw_whitening()

Simplify crypt_iv_tcw_whitening() by using crypto_shash_digest() instead
of an init+update+final sequence.  This should also improve performance.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 8a03b359073327b3268bbf9b2ba63bc3657b6c3c..4b5c54d0c51a6bbf5319c520a929613b16e2eeee 100644 (file)
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -652,13 +652,7 @@ static int crypt_iv_tcw_whitening(struct crypt_config *cc,
        /* calculate crc32 for every 32bit part and xor it */
        desc->tfm = tcw->crc32_tfm;
        for (i = 0; i < 4; i++) {
-               r = crypto_shash_init(desc);
-               if (r)
-                       goto out;
-               r = crypto_shash_update(desc, &buf[i * 4], 4);
-               if (r)
-                       goto out;
-               r = crypto_shash_final(desc, &buf[i * 4]);
+               r = crypto_shash_digest(desc, &buf[i * 4], 4, &buf[i * 4]);
                if (r)
                        goto out;
        }