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    SubjectRe: [patch] spinlocks: remove 'volatile'


    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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