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Date:   Thu, 17 Oct 2019 14:13:01 -0400
From:   Dennis Zhou <dennis@kernel.org>
To:     Ben Dooks <ben.dooks@codethink.co.uk>
Cc:     linux-kernel@lists.codethink.co.uk,
        Dennis Zhou <dennis@kernel.org>, Tejun Heo <tj@kernel.org>,
        Christoph Lameter <cl@linux.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] percpu: add __percpu to SHIFT_PERCPU_PTR
Message-ID: <20191017181301.GA32546@dennisz-mbp.dhcp.thefacebook.com>
References: <20191015102615.11430-1-ben.dooks@codethink.co.uk>
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On Tue, Oct 15, 2019 at 11:26:15AM +0100, Ben Dooks wrote:
> The SHIFT_PERCPU_PTR() returns a pointer used by a number
> of functions that expect the pointer to be __percpu annotated
> (sparse address space 3). Adding __percpu to this makes the
> following sparse warnings go away.
> 
> Note, this then creates the problem the __percup is marked
> as noderef, which may need removing for some of the internal
> functions, or to remove other warnings.
> 
> mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:385:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:385:13:    got signed char *
> mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:385:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:385:13:    got signed char *
> mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:385:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:385:13:    got signed char *
> mm/vmstat.c:385:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:385:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:385:13:    got signed char *
> mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:401:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:401:13:    got signed char *
> mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:401:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:401:13:    got signed char *
> mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:401:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:401:13:    got signed char *
> mm/vmstat.c:401:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:401:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:401:13:    got signed char *
> mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:429:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:429:13:    got signed char *
> mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:429:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:429:13:    got signed char *
> mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:429:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:429:13:    got signed char *
> mm/vmstat.c:429:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:429:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:429:13:    got signed char *
> mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:445:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:445:13:    got signed char *
> mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:445:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:445:13:    got signed char *
> mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:445:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:445:13:    got signed char *
> mm/vmstat.c:445:13: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:445:13:    expected signed char [noderef] [usertype] <asn:3> *__p
> mm/vmstat.c:445:13:    got signed char *
> mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:763:29:    expected signed char [noderef] <asn:3> *__p
> mm/vmstat.c:763:29:    got signed char *
> mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:763:29:    expected signed char [noderef] <asn:3> *__p
> mm/vmstat.c:763:29:    got signed char *
> mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:763:29:    expected signed char [noderef] <asn:3> *__p
> mm/vmstat.c:763:29:    got signed char *
> mm/vmstat.c:763:29: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:763:29:    expected signed char [noderef] <asn:3> *__p
> mm/vmstat.c:763:29:    got signed char *
> mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:825:29:    expected signed char [noderef] <asn:3> *__p
> mm/vmstat.c:825:29:    got signed char *
> mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:825:29:    expected signed char [noderef] <asn:3> *__p
> mm/vmstat.c:825:29:    got signed char *
> mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:825:29:    expected signed char [noderef] <asn:3> *__p
> mm/vmstat.c:825:29:    got signed char *
> mm/vmstat.c:825:29: warning: incorrect type in initializer (different address spaces)
> mm/vmstat.c:825:29:    expected signed char [noderef] <asn:3> *__p
> mm/vmstat.c:825:29:    got signed char *
> 
> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
> ---
> Cc: Dennis Zhou <dennis@kernel.org>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Christoph Lameter <cl@linux.com>
> Cc: linux-kernel@vger.kernel.org
> ---
>  include/linux/percpu-defs.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h
> index a6fabd865211..a49b6c702598 100644
> --- a/include/linux/percpu-defs.h
> +++ b/include/linux/percpu-defs.h
> @@ -229,7 +229,7 @@ do {									\
>   * pointer value.  The weird cast keeps both GCC and sparse happy.
>   */
>  #define SHIFT_PERCPU_PTR(__p, __offset)					\
> -	RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset))
> +	RELOC_HIDE((typeof(*(__p)) __kernel __percpu __force *)(__p), (__offset))
>  
>  #define per_cpu_ptr(ptr, cpu)						\
>  ({									\
> -- 
> 2.23.0
> 

Hello,

I've applied it for-5.5.

Thanks,
Dennis