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Date: Sat, 7 Apr 2007 15:15:56 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: Dave Jones <davej@redhat.com>, "Ulrich Drepper" <drepper@gmail.com>,
       "Nick Piggin" <nickpiggin@yahoo.com.au>, "Ingo Molnar" <mingo@elte.hu>,
       "Andi Kleen" <ak@suse.de>,
       "Ravikiran G Thirumalai" <kiran@scalex86.org>,
       "Shai Fultheim (Shai@scalex86.org)" <shai@scalex86.org>,
       "pravin b shelar" <pravin.shelar@calsoftinc.com>,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH, take4] FUTEX : new PRIVATE futexes
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On Sat, 7 Apr 2007 10:43:39 +0200 Eric Dumazet <dada1@cosmosbay.com> wrote:

> Hi all
> 
> Updates on this take4 :
> 
> - All remarks from Nick were addressed I hope
> 
> - Current mm code have a problem with 64bit futexes, as spoted by Nick :
> 
> get_futex_key() does a check against sizeof(u32) regardless of futex being 64bits or not.
> So it is possible a 64bit futex spans two pages of memory...
> I had to change get_futex_key() prototype to be able to do a correct test.
> 

Cold we please have that in a separate patch?  It's logically a part of the
64-bit-futex work, is it not?

> +
> +/**
> + * get_futex_key - Get parameters which are the keys for a futex.
> + * @uaddr: virtual address of the futex
> + * @size: size of futex (4 or 8)
> + * @shared: NULL for a PROCESS_PRIVATE futex,
> + *	&current->mm->mmap_sem for a PROCESS_SHARED futex
> + * @key: address where result is stored.
> + *
> + * Returns an error code or 0
> + */
> +int get_futex_key(void __user *uaddr, int size, struct rw_semaphore *shared,
> +		  union futex_key *key);

Thanks for documenting the interface, but please do it in the .c file at
the function's definition site.