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_ctr -> ctr(p8_aes) -> aes-generic
However p8_aes will always delegate its calls to aes-generic. With this
patch, p8_aes_ctr will be able to use ctr(aes-generic) directly as its
fallback. The same applies to aes_s390.
Signed-off-by: Marcelo Henrique Cerri <marcelo.ce...@canonical.com>
---
crypto/ctr.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/crypto/ctr.c b/crypto/ctr.c
index a4f4a89..3afe21a 100644
--- a/crypto/ctr.c
+++ b/crypto/ctr.c
@@ -181,15 +181,24 @@ static void crypto_ctr_exit_tfm(struct crypto_tfm *tfm)
static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb)
{
struct crypto_instance *inst;
+ struct crypto_attr_type *algt;
struct crypto_alg *alg;
+ u32 mask;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
if (err)
return ERR_PTR(err);
- alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
- CRYPTO_ALG_TYPE_MASK);
+ 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_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER, mask);
if (IS_ERR(alg))
return ERR_CAST(alg);
--
2.7.4
