Commit 6a805864 authored by Eric Biggers's avatar Eric Biggers Committed by Herbert Xu
Browse files

crypto: x86/aes-xts - simplify loop in xts_crypt_slowpath() 



Since the total length processed by the loop in xts_crypt_slowpath() is
a multiple of AES_BLOCK_SIZE, just round the length down to
AES_BLOCK_SIZE even on the last step.  This doesn't change behavior, as
the last step will process a multiple of AES_BLOCK_SIZE regardless.

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent c819d7b8

arch/x86/crypto/aesni-intel_glue.c

+5 −8
Original line number Diff line number Diff line
@@ -935,16 +935,13 @@ xts_crypt_slowpath(struct skcipher_request *req, xts_crypt_func crypt_func) 
	err = skcipher_walk_virt(&walk, req, false);



	while (walk.nbytes) {

		unsigned int nbytes = walk.nbytes;



		if (nbytes < walk.total)

			nbytes = round_down(nbytes, AES_BLOCK_SIZE);



		kernel_fpu_begin();

		(*crypt_func)(&ctx->crypt_ctx, walk.src.virt.addr,

			      walk.dst.virt.addr, nbytes, req->iv);

		(*crypt_func)(&ctx->crypt_ctx,

			      walk.src.virt.addr, walk.dst.virt.addr,

			      walk.nbytes & ~(AES_BLOCK_SIZE - 1), req->iv);

		kernel_fpu_end();

		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);

		err = skcipher_walk_done(&walk,

					 walk.nbytes & (AES_BLOCK_SIZE - 1));

	}



	if (err || !tail)