Re: [patch] spinlocks: remove 'volatile'

[Linus Torvalds]

On Thu, 6 Jul 2006, Jan Engelhardt wrote:
> >
> > You need to exclude "asm volatile", which is a completely different thing.
> 
> 10077.

Yeah, way too many. 

That said, at least _some_ of them are:

 - casts to volatile inside arch-specific code serquences (ie the _good_ 
   kind of volatile - associated with _code_ rather than data). 

   See for example include/asm-i386/io.h for 100% valid examples of this
   kind of usage.

 - function argument values for functions that need to be able to take an 
   arbitrary pointer ("const volatile void *" is the most permissive 
   argument type - anything else the compiler can complain about you 
   dropping qualifiers)

   See include/asm-i386/bitops.h for examples of this kind of volatile.

So I'd expect that maybe one percent of them are actually valid ;)

And I suspect that a huge majority of the truly crapola ones are in 
drivers. Oh, well..

			Linus
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