Re: [patch] spinlocks: remove 'volatile'

David Miller
2006-07-09T06:13:21Z

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.