[patch 27/40] powerpc: is_hugepage_only_range() must account for both 4kB and 64kB slices

Greg KH
2009-01-23T06:26:43Z

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2.6.27-stable review patch. If anyone has any objections, please let us know.

------------------

From: Dave Kleikamp <shaggy@linux.vnet.ibm.com>

commit 9ba0fdbfaed2e74005d87fab948c5522b86ff733 upstream.

powerpc: is_hugepage_only_range() must account for both 4kB and 64kB slices

The subpage_prot syscall fails on second and subsequent calls for a given
region, because is_hugepage_only_range() is mis-identifying the 4 kB
slices when the process has a 64 kB page size.

Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/powerpc/mm/slice.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

--- a/arch/powerpc/mm/slice.c
+++ b/arch/powerpc/mm/slice.c
@@ -710,9 +710,18 @@ int is_hugepage_only_range(struct mm_str
unsigned long len)
{
struct slice_mask mask, available;
+ unsigned int psize = mm->context.user_psize;

mask = slice_range_to_mask(addr, len);
- available = slice_mask_for_size(mm, mm->context.user_psize);
+ available = slice_mask_for_size(mm, psize);
+#ifdef CONFIG_PPC_64K_PAGES
+ /* We need to account for 4k slices too */
+ if (psize == MMU_PAGE_64K) {
+ struct slice_mask compat_mask;
+ compat_mask = slice_mask_for_size(mm, MMU_PAGE_4K);
+ or_mask(available, compat_mask);
+ }
+#endif

#if 0 /* too verbose */
slice_dbg("is_hugepage_only_range(mm=%p, addr=%lx, len=%lx)\n",