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crypto: cbc - Propagate NEED_FALLBACK bit

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When requesting a fallback algorithm, we should propagate the
NEED_FALLBACK bit when search for the underlying algorithm.

This will prevents drivers from allocating unnecessary fallbacks that
are never called. For instance, currently the vmx-crypto driver will use
the following chain of calls when calling the fallback implementation:

p8_aes_cbc -> cbc(p8_aes) -> aes-generic

However p8_aes will always delegate its calls to aes-generic. With this
patch, p8_aes_cbc will be able to use cbc(aes-generic) directly as its
fallback. The same applies to aes_s390.

Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Marcelo Cerri 2017-02-27 09:38:25 -03:00 committed by Herbert Xu
parent b13b1e0c6b
commit e6c2e65c70
1 changed files with 13 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

15
crypto/cbc.c
View file

@ -10,6 +10,7 @@
*
*/
#include <crypto/algapi.h>
#include <crypto/cbc.h>
#include <crypto/internal/skcipher.h>
#include <linux/err.h>
@ -108,8 +109,10 @@ static void crypto_cbc_free(struct skcipher_instance *inst)
static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
{
struct skcipher_instance *inst;
struct crypto_attr_type *algt;
struct crypto_spawn *spawn;
struct crypto_alg *alg;
u32 mask;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER);
@ -120,8 +123,16 @@ static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
if (!inst)
return -ENOMEM;
alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
CRYPTO_ALG_TYPE_MASK);
algt = crypto_get_attr_type(tb);
err = PTR_ERR(algt);
if (IS_ERR(algt))
goto err_free_inst;
mask = CRYPTO_ALG_TYPE_MASK |
crypto_requires_off(algt->type, algt->mask,
CRYPTO_ALG_NEED_FALLBACK);
alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, mask);
err = PTR_ERR(alg);
if (IS_ERR(alg))
goto err_free_inst;