Messages in this thread | | | Date | Mon, 12 Jan 2009 22:12:30 +0100 | From | Ingo Molnar <> | Subject | Re: [git pull] x86 fixes |
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* Harvey Harrison <harvey.harrison@gmail.com> wrote:
> On Mon, 2009-01-12 at 21:52 +0100, Ingo Molnar wrote: > > * Linus Torvalds <torvalds@linux-foundation.org> wrote: > > > +static inline int is_new_memtype_allowed(unsigned long flags, > > + unsigned long new_flags) > > +{ > > + /* > > + * Certain new memtypes are not allowed with certain > > + * requested memtype: > > + * - request is uncached, return cannot be write-back > > + * - request is write-combine, return cannot be write-back > > + */ > > + if ((flags == _PAGE_CACHE_UC_MINUS && > > + new_flags == _PAGE_CACHE_WB) || > > + (flags == _PAGE_CACHE_WC && > > + new_flags == _PAGE_CACHE_WB)) { > > + return 0; > > + } > > if ((flags == _PAGE_CACHE_UC_MINUS || flags == _PAGE_CACHE_WC) && > (new_flags == _PAGE_CACHE_WB)) > > might be a bit neater perhaps.
indeed. The most readable one is probably:
static inline int is_new_memtype_allowed(unsigned long flags, unsigned long new_flags) { /* * Certain new memtypes are not allowed with certain * requested memtype: * - request is uncached, return cannot be write-back * - request is write-combine, return cannot be write-back */
if (new_flags != _PAGE_CACHE_WB) return 1;
if (flags == _PAGE_CACHE_UC_MINUS) return 0; if (flags == _PAGE_CACHE_WC) return 0;
return 1; }
Ingo
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