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Date: Sat, 08 Jul 2006 23:13:51 -0700 (PDT)
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To: torvalds@osdl.org
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Subject: Re: [patch] spinlocks: remove 'volatile' 
From: David Miller <davem@davemloft.net>
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From: Linus Torvalds <torvalds@osdl.org>
Date: Sat, 8 Jul 2006 20:58:37 -0700 (PDT)

> We can certainly write
> 
> 	...
> 	:"=m" (*ptr)
> 	:"m" (*ptr)
> 	...
> 
> instead of the much simpler
> 
> 	:"+m" (*ptr)
> 
> but we've been using that "+m" format for a long time already (and I 
> _think_ we did so at the suggestion of gcc people), and it would be much 
> better if the gcc documentation was just fixed here.

I honestly don't know why that language is there about '+' saying to
only use it when the constraints allow a register.  Perhaps there are
some implications for reload.