[PATCH] crypto: chacha-generic - use crypto_xor_cpy()

[Eric Biggers]

From: Eric Biggers <ebigg...@google.com>

In chacha_docrypt(), use crypto_xor_cpy() instead of crypto_xor().
This avoids having to memcpy() the src buffer to the dst buffer.

Signed-off-by: Eric Biggers <ebigg...@google.com>
---
 crypto/chacha_generic.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/crypto/chacha_generic.c b/crypto/chacha_generic.c
index 90ec0ec1b4f7..a7fae9b73ec4 100644
--- a/crypto/chacha_generic.c
+++ b/crypto/chacha_generic.c
@@ -22,18 +22,16 @@ static void chacha_docrypt(u32 *state, u8 *dst, const u8 
*src,
        /* aligned to potentially speed up crypto_xor() */
        u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long));
 
-       if (dst != src)
-               memcpy(dst, src, bytes);
-
        while (bytes >= CHACHA_BLOCK_SIZE) {
                chacha_block(state, stream, nrounds);
-               crypto_xor(dst, stream, CHACHA_BLOCK_SIZE);
+               crypto_xor_cpy(dst, src, stream, CHACHA_BLOCK_SIZE);
                bytes -= CHACHA_BLOCK_SIZE;
                dst += CHACHA_BLOCK_SIZE;
+               src += CHACHA_BLOCK_SIZE;
        }
        if (bytes) {
                chacha_block(state, stream, nrounds);
-               crypto_xor(dst, stream, bytes);
+               crypto_xor_cpy(dst, src, stream, bytes);
        }
 }
 
-- 
2.21.0