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ARM: Fix pfn_valid() for sparse memory

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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>
This commit is contained in:
Russell King 2009-09-07 15:06:42 +01:00 • committed by Russell King
parent 5eb38f4483
commit b7cfda9fc3
3 changed files with 36 additions and 17 deletions
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32
arch/arm/mm/init.c
View file

@ -15,6 +15,7 @@
#include <linux/mman.h>
#include <linux/nodemask.h>
#include <linux/initrd.h>
#include <linux/sort.h>
#include <linux/highmem.h>
#include <asm/mach-types.h>
@ -349,12 +350,43 @@ static void __init bootmem_free_node(int node, struct meminfo *mi)
free_area_init_node(node, zone_size, min, zhole_size);
}
#ifndef CONFIG_SPARSEMEM
int pfn_valid(unsigned long pfn)
{
struct meminfo *mi = &meminfo;
unsigned int left = 0, right = mi->nr_banks;
do {
unsigned int mid = (right + left) / 2;
struct membank *bank = &mi->bank[mid];
if (pfn < bank_pfn_start(bank))
right = mid;
else if (pfn >= bank_pfn_end(bank))
left = mid + 1;
else
return 1;
} while (left < right);
return 0;
}
EXPORT_SYMBOL(pfn_valid);
#endif
static int __init meminfo_cmp(const void *_a, const void *_b)
{
const struct membank *a = _a, *b = _b;
long cmp = bank_pfn_start(a) - bank_pfn_start(b);
return cmp < 0 ? -1 : cmp > 0 ? 1 : 0;
}
void __init bootmem_init(void)
{
struct meminfo *mi = &meminfo;
unsigned long min, max_low, max_high;
int node, initrd_node;
sort(&mi->bank, mi->nr_banks, sizeof(mi->bank[0]), meminfo_cmp, NULL);
/*
* Locate which node contains the ramdisk image, if any.
*/