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@xxxxxxxxxxxxx>
---
crypto/cbc.c | 20 ++++++++++++++------
1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/crypto/cbc.c b/crypto/cbc.c
index bc160a3..7147842 100644
--- a/crypto/cbc.c
+++ b/crypto/cbc.c
@@ -108,24 +108,32 @@ 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);
if (err)
return err;
+ algt = crypto_get_attr_type(tb);
+ if (IS_ERR(algt))
+ return PTR_ERR(algt);
+
+ 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);
+ if (IS_ERR(alg))
+ return PTR_ERR(alg);
+
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return -ENOMEM;
- alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
- CRYPTO_ALG_TYPE_MASK);
- err = PTR_ERR(alg);
- if (IS_ERR(alg))
- goto err_free_inst;
-
spawn = skcipher_instance_ctx(inst);
err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
CRYPTO_ALG_TYPE_MASK);
--
2.7.4
