From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH 7/8] percpu: add __percpu sparse annotations to	hw_breakpoint
Date: Tue, 26 Jan 2010 11:43:56 +0900
Message-ID: <4B5E56EC.2090600@kernel.org>
References: <1264432935-10453-1-git-send-email-tj@kernel.org> <1264432935-10453-8-git-send-email-tj@kernel.org> <20100126001901.GI5087@nowhere> <4B5E3F2C.2010702@zytor.com> <4B5E4E12.7060900@kernel.org> <20100126020452.GB19799@ZenIV.linux.org.uk> <4B5E508A.1030305@kernel.org> <20100126023238.GC19799@ZenIV.linux.org.uk>
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Cc: "H. Peter Anvin" <hpa@zytor.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	linux-kernel@vger.kernel.org, axboe@kernel.dk,
	rusty@rustcorp.com.au, akpm@linux-foundation.org,
	ebiederm@xmission.com, tytso@mit.edu, Trond.Myklebust@netapp.com,
	aelder@sgi.com, hch@infradead.org, davem@davemloft.net,
	netdev@vger.kernel.org, x86@kernel.org, mingo@redhat.com,
	dan.j.williams@intel.com, borislav.petkov@amd.com,
	ying.huang@intel.com, lenb@kernel.org, neilb@suse.de,
	cl@linux-foundation.org
To: Al Viro <viro@ZenIV.linux.org.uk>
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Hello,

On 01/26/2010 11:32 AM, Al Viro wrote:
> On Tue, Jan 26, 2010 at 11:16:42AM +0900, Tejun Heo wrote:
> 
>> # define RELOC_HIDE(ptr, off)					\
>>   ({ unsigned long __ptr;					\
>>      __ptr = (unsigned long) (ptr);				\
>>     (typeof(ptr)) (__ptr + (off)); })
>>
>> #define __verify_pcpu_ptr(ptr)	do {					\
>> 	const void __percpu *__vpp_verify = (typeof(ptr))NULL;		\
>> 	(void)__vpp_verify;						\
>> } while (0)
>>
>> /* Weird cast keeps both GCC and sparse happy. */
>> #define SHIFT_PERCPU_PTR(__p, __offset)	({				\
>> 	__verify_pcpu_ptr((__p));					\
>> 	RELOC_HIDE((typeof(*(__p)) __kernel __force *)(__p), (__offset)); \
>> })
>>
>> #define per_cpu(var, cpu) \
>> 	(*SHIFT_PERCPU_PTR(&(var), per_cpu_offset(cpu)))
> 
> Eh...  You are leaving that noderef in place in case of array.  And _that_
> is not an address space, so casts to AS 0 won't do you any good.

Any ideas on how to fix it?

Thanks.

-- 
tejun