From dca0ae3900b3836ca50a14e488057090d8559c28 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 9 May 2020 15:58:04 -0700 Subject: [PATCH] gcc-10: avoid shadowing standard library 'free()' in crypto MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 1a263ae60b04de959d9ce9caea4889385eefcc7b upstream. gcc-10 has started warning about conflicting types for a few new built-in functions, particularly 'free()'. This results in warnings like: crypto/xts.c:325:13: warning: conflicting types for built-in function ‘free’; expected ‘void(void *)’ [-Wbuiltin-declaration-mismatch] because the crypto layer had its local freeing functions called 'free()'. Gcc-10 is in the wrong here, since that function is marked 'static', and thus there is no chance of confusion with any standard library function namespace. But the simplest thing to do is to just use a different name here, and avoid this gcc mis-feature. [ Side note: gcc knowing about 'free()' is in itself not the mis-feature: the semantics of 'free()' are special enough that a compiler can validly do special things when seeing it. So the mis-feature here is that gcc thinks that 'free()' is some restricted name, and you can't shadow it as a local static function. Making the special 'free()' semantics be a function attribute rather than tied to the name would be the much better model ] Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- crypto/lrw.c | 4 ++-- crypto/xts.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/crypto/lrw.c b/crypto/lrw.c index be829f6afc8e..3d40e1f32bea 100644 --- a/crypto/lrw.c +++ b/crypto/lrw.c @@ -289,7 +289,7 @@ static void exit_tfm(struct crypto_skcipher *tfm) crypto_free_skcipher(ctx->child); } -static void free(struct skcipher_instance *inst) +static void free_inst(struct skcipher_instance *inst) { crypto_drop_skcipher(skcipher_instance_ctx(inst)); kfree(inst); @@ -401,7 +401,7 @@ static int create(struct crypto_template *tmpl, struct rtattr **tb) inst->alg.encrypt = encrypt; inst->alg.decrypt = decrypt; - inst->free = free; + inst->free = free_inst; err = skcipher_register_instance(tmpl, inst); if (err) diff --git a/crypto/xts.c b/crypto/xts.c index ab117633d64e..9d72429f666e 100644 --- a/crypto/xts.c +++ b/crypto/xts.c @@ -328,7 +328,7 @@ static void exit_tfm(struct crypto_skcipher *tfm) crypto_free_cipher(ctx->tweak); } -static void free(struct skcipher_instance *inst) +static void free_inst(struct skcipher_instance *inst) { crypto_drop_skcipher(skcipher_instance_ctx(inst)); kfree(inst); @@ -439,7 +439,7 @@ static int create(struct crypto_template *tmpl, struct rtattr **tb) inst->alg.encrypt = encrypt; inst->alg.decrypt = decrypt; - inst->free = free; + inst->free = free_inst; err = skcipher_register_instance(tmpl, inst); if (err)