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    SubjectRe: [PATCH] Fix __pfn_to_page(pfn) for CONFIG_DISCONTIGMEM=y
    Hi!

    > This would be good to have in .28 IMO.

    Actually, this makes sense even for .27-stable, AFAICT.

    > From: Rafael J. Wysocki <rjw@sisk.pl>
    > Subject: Fix __pfn_to_page(pfn) for CONFIG_DISCONTIGMEM=y
    >
    > Fix macro __pfn_to_page(pfn) so that it doesn't evaluate its
    > argument twice in the CONFIG_DISCONTIGMEM=y case, because 'pfn' may
    > be a result of a funtion call having side effects.

    function call?

    > For example, the hibernation code applies pfn_to_page(pfn) to the
    > result of a function returning the pfn corresponding to the next set
    > bit in a bitmap and the current bit position is modified on each
    > call. This leads to "interesting" failures for CONFIG_DISCONTIGMEM=y
    > due to the current behavior of __pfn_to_page(pfn).
    >
    > Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
    > Cc: Pavel Machek <pavel@suse.cz>

    Acked-by: Pavel Machek <pavel@suse.cz>


    > include/asm-generic/memory_model.h | 2 +-
    > 1 file changed, 1 insertion(+), 1 deletion(-)
    >
    > Index: linux-2.6/include/asm-generic/memory_model.h
    > ===================================================================
    > --- linux-2.6.orig/include/asm-generic/memory_model.h
    > +++ linux-2.6/include/asm-generic/memory_model.h
    > @@ -34,7 +34,7 @@
    >
    > #define __pfn_to_page(pfn) \
    > ({ unsigned long __pfn = (pfn); \
    > - unsigned long __nid = arch_pfn_to_nid(pfn); \
    > + unsigned long __nid = arch_pfn_to_nid(__pfn); \
    > NODE_DATA(__nid)->node_mem_map + arch_local_page_offset(__pfn, __nid);\
    > })
    >

    --
    (english) http://www.livejournal.com/~pavelmachek
    (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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