Re: [patch] spinlocks: remove 'volatile'

From: David Miller
Date: Sun Jul 09 2006 - 02:11:33 EST


From: Linus Torvalds <torvalds@xxxxxxxx>
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.
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