Commit e71778c9 authored by Eric Biggers's avatar Eric Biggers Committed by Herbert Xu
Browse files

crypto: skcipher - document skcipher_walk_done() and rename some vars 



skcipher_walk_done() has an unusual calling convention, and some of its
local variables have unclear names.  Document it and rename variables to
make it a bit clearer what is going on.  No change in behavior.

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 42c5675c

crypto/skcipher.c

+34 −16
Original line number Diff line number Diff line
@@ -89,17 +89,35 @@ static int skcipher_done_slow(struct skcipher_walk *walk, unsigned int bsize) 
	return 0;

}



int skcipher_walk_done(struct skcipher_walk *walk, int err)

/**

 * skcipher_walk_done() - finish one step of a skcipher_walk

 * @walk: the skcipher_walk

 * @res: number of bytes *not* processed (>= 0) from walk->nbytes,

 *	 or a -errno value to terminate the walk due to an error

 *

 * This function cleans up after one step of walking through the source and

 * destination scatterlists, and advances to the next step if applicable.

 * walk->nbytes is set to the number of bytes available in the next step,

 * walk->total is set to the new total number of bytes remaining, and

 * walk->{src,dst}.virt.addr is set to the next pair of data pointers.  If there

 * is no more data, or if an error occurred (i.e. -errno return), then

 * walk->nbytes and walk->total are set to 0 and all resources owned by the

 * skcipher_walk are freed.

 *

 * Return: 0 or a -errno value.  If @res was a -errno value then it will be

 *	   returned, but other errors may occur too.

 */

int skcipher_walk_done(struct skcipher_walk *walk, int res)

{

	unsigned int n = walk->nbytes;

	unsigned int nbytes = 0;

	unsigned int n = walk->nbytes; /* num bytes processed this step */

	unsigned int total = 0; /* new total remaining */



	if (!n)

		goto finish;



	if (likely(err >= 0)) {

		n -= err;

		nbytes = walk->total - n;

	if (likely(res >= 0)) {

		n -= res; /* subtract num bytes *not* processed */

		total = walk->total - n;

	}



	if (likely(!(walk->flags & (SKCIPHER_WALK_SLOW |
@@ -115,31 +133,31 @@ int skcipher_walk_done(struct skcipher_walk *walk, int err) 
		memcpy(walk->dst.virt.addr, walk->page, n);

		skcipher_unmap_dst(walk);

	} else if (unlikely(walk->flags & SKCIPHER_WALK_SLOW)) {

		if (err > 0) {

		if (res > 0) {

			/*

			 * Didn't process all bytes.  Either the algorithm is

			 * broken, or this was the last step and it turned out

			 * the message wasn't evenly divisible into blocks but

			 * the algorithm requires it.

			 */

			err = -EINVAL;

			nbytes = 0;

			res = -EINVAL;

			total = 0;

		} else

			n = skcipher_done_slow(walk, n);

	}



	if (err > 0)

		err = 0;

	if (res > 0)

		res = 0;



	walk->total = nbytes;

	walk->total = total;

	walk->nbytes = 0;



	scatterwalk_advance(&walk->in, n);

	scatterwalk_advance(&walk->out, n);

	scatterwalk_done(&walk->in, 0, nbytes);

	scatterwalk_done(&walk->out, 1, nbytes);

	scatterwalk_done(&walk->in, 0, total);

	scatterwalk_done(&walk->out, 1, total);



	if (nbytes) {

	if (total) {

		crypto_yield(walk->flags & SKCIPHER_WALK_SLEEP ?

			     CRYPTO_TFM_REQ_MAY_SLEEP : 0);

		return skcipher_walk_next(walk);
@@ -158,7 +176,7 @@ int skcipher_walk_done(struct skcipher_walk *walk, int err) 
		free_page((unsigned long)walk->page);



out:

	return err;

	return res;

}

EXPORT_SYMBOL_GPL(skcipher_walk_done);

include/crypto/internal/skcipher.h

+1 −1
Original line number Diff line number Diff line
@@ -196,7 +196,7 @@ void crypto_unregister_lskciphers(struct lskcipher_alg *algs, int count); 
int lskcipher_register_instance(struct crypto_template *tmpl,

				struct lskcipher_instance *inst);



int skcipher_walk_done(struct skcipher_walk *walk, int err);

int skcipher_walk_done(struct skcipher_walk *walk, int res);

int skcipher_walk_virt(struct skcipher_walk *walk,

		       struct skcipher_request *req,

		       bool atomic);