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Revision 1f64d69c7ad2e48e697493e45590679f7a69b7b2 authored by Dean Nelson on 02 December 2010, 22:31:12 UTC, committed by Linus Torvalds on 02 December 2010, 22:51:14 UTC 
mm/hugetlb.c: avoid double unlock_page() in hugetlb_fault()
 
Have hugetlb_fault() call unlock_page(page) only if it had previously
called lock_page(page).

Setting CONFIG_DEBUG_VM=y and then running the libhugetlbfs test suite,
resulted in the tripping of VM_BUG_ON(!PageLocked(page)) in
unlock_page() having been called by hugetlb_fault() when page ==
pagecache_page.  This patch remedied the problem.

Signed-off-by: Dean Nelson <dnelson@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 94c35de
Raw File
iommu-helper.c 
/*
 * IOMMU helper functions for the free area management
 */

#include <linux/module.h>
#include <linux/bitmap.h>

int iommu_is_span_boundary(unsigned int index, unsigned int nr,
			   unsigned long shift,
			   unsigned long boundary_size)
{
	BUG_ON(!is_power_of_2(boundary_size));

	shift = (shift + index) & (boundary_size - 1);
	return shift + nr > boundary_size;
}

unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
			       unsigned long start, unsigned int nr,
			       unsigned long shift, unsigned long boundary_size,
			       unsigned long align_mask)
{
	unsigned long index;

	/* We don't want the last of the limit */
	size -= 1;
again:
	index = bitmap_find_next_zero_area(map, size, start, nr, align_mask);
	if (index < size) {
		if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
			/* we could do more effectively */
			start = index + 1;
			goto again;
		}
		bitmap_set(map, index, nr);
		return index;
	}
	return -1;
}
EXPORT_SYMBOL(iommu_area_alloc);
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