Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <855ea9f7-5f0a-68a3-eece-6e9c1b27e90b@huawei.com>
Date:   Wed, 13 Apr 2022 14:01:19 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
 Thunderbird/91.6.1
Subject: Re: [RFC PATCH -next V3 1/6] x86: fix function define in
 copy_mc_to_user
To:     Kefeng Wang <wangkefeng.wang@huawei.com>,
        Mark Rutland <mark.rutland@arm.com>,
        James Morse <james.morse@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        "Ingo Molnar" <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Robin Murphy <robin.murphy@arm.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "Catalin Marinas" <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        "Alexander Viro" <viro@zeniv.linux.org.uk>, <x86@kernel.org>,
        "H . Peter Anvin" <hpa@zytor.com>
CC:     <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
        Xie XiuQi <xiexiuqi@huawei.com>
References: <20220412072552.2526871-1-tongtiangen@huawei.com>
 <20220412072552.2526871-2-tongtiangen@huawei.com>
 <cd01ee8b-6686-fe8e-0d02-5507165f55eb@huawei.com>
From:   Tong Tiangen <tongtiangen@huawei.com>
In-Reply-To: <cd01ee8b-6686-fe8e-0d02-5507165f55eb@huawei.com>
Content-Type: text/plain; charset="UTF-8"; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk


在 2022/4/12 19:49, Kefeng Wang 写道:
> 
> On 2022/4/12 15:25, Tong Tiangen wrote:
>> X86 has it's implementation of copy_mc_to_user but not use #define to
>> declare.
>>
>> This may cause problems, for example, if other architectures open
>> CONFIG_ARCH_HAS_COPY_MC, but want to use copy_mc_to_user() outside the
>> architecture, the code add to include/linux/uaddess.h is as follows:
>>
>>      #ifndef copy_mc_to_user
>>      static inline unsigned long __must_check
>>      copy_mc_to_user(void *dst, const void *src, size_t cnt)
>>      {
>>         ...
>>      }
>>      #endif
>>
>> Then this definition will conflict with the implementation of X86 and 
>> cause
>> compilation errors.
> Does powerpc need this define?

Oh, missing that, will do next version.
>>
>> Fixes: ec6347bb4339 ("x86, powerpc: Rename memcpy_mcsafe() to 
>> copy_mc_to_{user, kernel}()")
>> Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
>> ---
>>   arch/x86/include/asm/uaccess.h | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/x86/include/asm/uaccess.h 
>> b/arch/x86/include/asm/uaccess.h
>> index f78e2b3501a1..e18c5f098025 100644
>> --- a/arch/x86/include/asm/uaccess.h
>> +++ b/arch/x86/include/asm/uaccess.h
>> @@ -415,6 +415,7 @@ copy_mc_to_kernel(void *to, const void *from, 
>> unsigned len);
>>   unsigned long __must_check
>>   copy_mc_to_user(void *to, const void *from, unsigned len);
>> +#define copy_mc_to_user copy_mc_to_user
>>   #endif
>>   /*
> .