crypto: atmel-tdes - Detecting in-place operations with two sg lists

Avoiding detecting finely in-place operations with different
scatter lists. Copying the source data for decryption into rctx->lastc
regardless if the operation is in-place or not. This allows in-place
operations with different scatter lists without affecting other
operations.

This approach takes less resources than parsing both scatter lists to
check if they are equal.

Signed-off-by: Ryan Wanner <Ryan.Wanner@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/atmel-tdes.c b/drivers/crypto/atmel-tdes.c
index b2d48c1..c9ded8b 100644 (file)
--- a/drivers/crypto/atmel-tdes.c
+++ b/drivers/crypto/atmel-tdes.c
@@ -565,17 +565,12 @@ atmel_tdes_set_iv_as_last_ciphertext_block(struct atmel_tdes_dev *dd)
        if (req->cryptlen < ivsize)
                return;
 
-       if (rctx->mode & TDES_FLAGS_ENCRYPT) {
+       if (rctx->mode & TDES_FLAGS_ENCRYPT)
                scatterwalk_map_and_copy(req->iv, req->dst,
                                         req->cryptlen - ivsize, ivsize, 0);
-       } else {
-               if (req->src == req->dst)
-                       memcpy(req->iv, rctx->lastc, ivsize);
-               else
-                       scatterwalk_map_and_copy(req->iv, req->src,
-                                                req->cryptlen - ivsize,
-                                                ivsize, 0);
-       }
+       else
+               memcpy(req->iv, rctx->lastc, ivsize);
+
 }
 
 static void atmel_tdes_finish_req(struct atmel_tdes_dev *dd, int err)
@@ -722,7 +717,7 @@ static int atmel_tdes_crypt(struct skcipher_request *req, unsigned long mode)
        rctx->mode = mode;
 
        if ((mode & TDES_FLAGS_OPMODE_MASK) != TDES_FLAGS_ECB &&
-           !(mode & TDES_FLAGS_ENCRYPT) && req->src == req->dst) {
+           !(mode & TDES_FLAGS_ENCRYPT)) {
                unsigned int ivsize = crypto_skcipher_ivsize(skcipher);
 
                if (req->cryptlen >= ivsize)