Re: [Qemu-trivial] [PATCH 6/7] crypto: remove useless casts

[Michael Tokarev]

15.06.2016 19:14, Laurent Vivier пишет:
> This patch is the result of coccinelle script
> scripts/coccinelle/typecast.cocci
>
> CC: Daniel P. Berrange <address@hidden>
> Signed-off-by: Laurent Vivier <address@hidden>
> ---
>  crypto/cipher-builtin.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/crypto/cipher-builtin.c b/crypto/cipher-builtin.c
> index 88963f6..d791c80 100644
> --- a/crypto/cipher-builtin.c
> +++ b/crypto/cipher-builtin.c
> @@ -132,7 +132,7 @@ static void qcrypto_cipher_aes_xts_encrypt(const void *ctx,
>  {
>      const QCryptoCipherBuiltinAESContext *aesctx = ctx;
>
> -    qcrypto_cipher_aes_ecb_encrypt((AES_KEY *)&aesctx->enc,
> +    qcrypto_cipher_aes_ecb_encrypt(&aesctx->enc,
>                                     src, dst, length);
>  }
>
> @@ -144,7 +144,7 @@ static void qcrypto_cipher_aes_xts_decrypt(const void *ctx,
>  {
>      const QCryptoCipherBuiltinAESContext *aesctx = ctx;
>
> -    qcrypto_cipher_aes_ecb_decrypt((AES_KEY *)&aesctx->dec,
> +    qcrypto_cipher_aes_ecb_decrypt(&aesctx->dec,
>                                     src, dst, length);
>  }

This patch causes the following build failure:

  CC    crypto/block.o
In file included from 
/build/qemu/git/crypto/cipher.c:156:0:crypto/cipher-builtin.c: In 
function ‘qcrypto_cipher_aes_xts_encrypt’:
crypto/cipher-builtin.c:135:36: error: passing argument 1 of 
‘qcrypto_cipher_aes_ecb_encrypt’ discards ‘const’ qualifier from pointer 
target type [-Werror]
     qcrypto_cipher_aes_ecb_encrypt(&aesctx->enc,
                                    ^
crypto/cipher-builtin.c:76:13: note: expected ‘struct AES_KEY *’ but 
argument is of type ‘const struct AES_KEY *’
 static void qcrypto_cipher_aes_ecb_encrypt(AES_KEY *key,
             ^
crypto/cipher-builtin.c: In function ‘qcrypto_cipher_aes_xts_decrypt’:
crypto/cipher-builtin.c:147:36: error: passing argument 1 of 
‘qcrypto_cipher_aes_ecb_decrypt’ discards ‘const’ qualifier from pointer 
target type [-Werror]
     qcrypto_cipher_aes_ecb_decrypt(&aesctx->dec,
                                    ^
crypto/cipher-builtin.c:102:13: note: expected ‘struct AES_KEY *’ but 
argument is of type ‘const struct AES_KEY *’
 static void qcrypto_cipher_aes_ecb_decrypt(AES_KEY *key,
             ^
cc1: all warnings being treated as errors

It's interesting that the qemu functions accepts const argument,
while apparently this is wrong, as qcrypto functions modifies their
args.  Looks like a bug either in qemu or qcrypto... :)

I'll reverted this change for now.

Thanks,

/mjt