From: Marcelo Henrique Cerri Subject: [PATCH 1/2] crypto: cbc - Propagate NEED_FALLBACK bit Date: Sun, 26 Feb 2017 22:03:18 -0300 Message-ID: <1488157399-3587-2-git-send-email-marcelo.cerri@canonical.com> References: <1488157399-3587-1-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: Received: from mail-qk0-f180.google.com ([209.85.220.180]:36240 "EHLO mail-qk0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751284AbdB0BDr (ORCPT ); Sun, 26 Feb 2017 20:03:47 -0500 Received: by mail-qk0-f180.google.com with SMTP id n186so445834qkb.3 for ; Sun, 26 Feb 2017 17:03:46 -0800 (PST) In-Reply-To: <1488157399-3587-1-git-send-email-marcelo.cerri@canonical.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: 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 | 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