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Subject: Re: [PATCH] crypto: arm64/aes-neonbs - remove redundant code in
 __xts_crypt()
To:     Ard Biesheuvel <ard.biesheuvel@linaro.org>
CC:     Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        "hushiyuan@huawei.com" <hushiyuan@huawei.com>,
        "linfeilong@huawei.com" <linfeilong@huawei.com>,
        "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" 
        <linux-crypto@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
References: <a33932c9-2975-4fcc-ba07-7c54df4eae27@huawei.com>
 <CAKv+Gu-qAy9iLbR97=Kz90+-YLLvz0nmTZtxhByeOXEG3xvaBQ@mail.gmail.com>
From:   Yunfeng Ye <yeyunfeng@huawei.com>
Message-ID: <43706330-cc84-d597-11ad-a3e0afb0b793@huawei.com>
Date:   Tue, 22 Oct 2019 15:14:58 +0800
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On 2019/10/22 14:52, Ard Biesheuvel wrote:
> On Tue, 22 Oct 2019 at 08:42, Yunfeng Ye <yeyunfeng@huawei.com> wrote:
>>
>> A warning is found by the static code analysis tool:
>>   "Identical condition 'err', second condition is always false"
>>
>> Fix this by removing the redundant condition @err.
>>
>> Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
> 
> Please don't blindly 'fix' crypto code without reading it carefully
> and without cc'ing the author.
> 
ok, thanks.

> The correct fix is to add the missing assignment of 'err', like so
> 
> diff --git a/arch/arm64/crypto/aes-neonbs-glue.c
> b/arch/arm64/crypto/aes-neonbs-glue.c
> index ea873b8904c4..e3e27349a9fe 100644
> --- a/arch/arm64/crypto/aes-neonbs-glue.c
> +++ b/arch/arm64/crypto/aes-neonbs-glue.c
> @@ -384,7 +384,7 @@ static int __xts_crypt(struct skcipher_request
> *req, bool encrypt,
>                         goto xts_tail;
> 
>                 kernel_neon_end();
> -               skcipher_walk_done(&walk, nbytes);
> +               err = skcipher_walk_done(&walk, nbytes);
>         }
> 
>         if (err || likely(!tail))
> 
> Does that make the warning go away?
> 
yes, warning has go way.

> 
>> ---
>>  arch/arm64/crypto/aes-neonbs-glue.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/crypto/aes-neonbs-glue.c b/arch/arm64/crypto/aes-neonbs-glue.c
>> index ea873b8904c4..7b342db428b0 100644
>> --- a/arch/arm64/crypto/aes-neonbs-glue.c
>> +++ b/arch/arm64/crypto/aes-neonbs-glue.c
>> @@ -387,7 +387,7 @@ static int __xts_crypt(struct skcipher_request *req, bool encrypt,
>>                 skcipher_walk_done(&walk, nbytes);
>>         }
>>
>> -       if (err || likely(!tail))
>> +       if (likely(!tail))
>>                 return err;
>>
>>         /* handle ciphertext stealing */
>> --
>> 2.7.4.3
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 
> .
>