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https://github.com/torvalds/linux
27 March 2024, 02:37:15 UTC
Revision 28db837693c84bc64e20d84aad00e2c0f206468a authored by Linus Torvalds on 13 March 2011, 22:50:37 UTC, committed by Linus Torvalds on 13 March 2011, 22:50:37 UTC 
Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
 
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  block: fix mis-synchronisation in blkdev_issue_zeroout()
2 parent s 4f680ce + 0aeea18
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Tip revision: 28db837693c84bc64e20d84aad00e2c0f206468a authored by Linus Torvalds on 13 March 2011, 22:50:37 UTC
Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
Tip revision: 28db837
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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