Commit e6c2e65c authored by Marcelo Cerri's avatar Marcelo Cerri Committed by Herbert Xu

crypto: cbc - Propagate NEED_FALLBACK bit

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: default avatarMarcelo Henrique Cerri <>
Signed-off-by: default avatarHerbert Xu <>
parent b13b1e0c
......@@ -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,
algt = crypto_get_attr_type(tb);
err = PTR_ERR(algt);
if (IS_ERR(algt))
goto err_free_inst;
crypto_requires_off(algt->type, algt->mask,
alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, mask);
err = PTR_ERR(alg);
if (IS_ERR(alg))
goto err_free_inst;
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