From: Marcelo Henrique Cerri Subject: [PATCH v2 1/2] crypto: cbc - Propagate NEED_FALLBACK bit Date: Mon, 27 Feb 2017 09:38:25 -0300 Message-ID: <1488199106-16061-2-git-send-email-marcelo.cerri@canonical.com> References: <1488199106-16061-1-git-send-email-marcelo.cerri@canonical.com> Cc: "David S. Miller" , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, Marcelo Henrique Cerri To: Herbert Xu Return-path: In-Reply-To: <1488199106-16061-1-git-send-email-marcelo.cerri@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org 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 --- crypto/cbc.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/crypto/cbc.c b/crypto/cbc.c index bc160a3..b761b1f 100644 --- a/crypto/cbc.c +++ b/crypto/cbc.c @@ -10,6 +10,7 @@ * */ +#include #include #include #include @@ -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; -- 2.7.4