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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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