ARM: Fix pfn_valid() for sparse memory
On OMAP platforms, some people want to declare to segment up the memory
between the kernel and a separate application such that there is a hole
in the middle of the memory as far as Linux is concerned. However,
they want to be able to mmap() the hole.
This currently causes problems, because update_mmu_cache() thinks that
there are valid struct pages for the "hole". Fix this by making
pfn_valid() slightly more expensive, by checking whether the PFN is
contained within the meminfo array.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Khasim Syed Mohammed <khasim@ti.com>
diff --git a/arch/arm/include/asm/page.h b/arch/arm/include/asm/page.h
index 9c746af..3a32af4 100644
--- a/arch/arm/include/asm/page.h
+++ b/arch/arm/include/asm/page.h
@@ -194,6 +194,10 @@
typedef struct page *pgtable_t;
+#ifndef CONFIG_SPARSEMEM
+extern int pfn_valid(unsigned long);
+#endif
+
#include <asm/memory.h>
#endif /* !__ASSEMBLY__ */