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23 October 2021, 00:29:24 UTC
Revision 3eab887a55424fc2c27553b7bfe32330df83f7b8 authored by Linus Torvalds on 28 August 2016, 22:04:33 UTC, committed by Linus Torvalds on 28 August 2016, 22:04:33 UTC 
Linux 4.8-rc4
1 parent 25d0d91
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Tip revision: 3eab887a55424fc2c27553b7bfe32330df83f7b8 authored by Linus Torvalds on 28 August 2016, 22:04:33 UTC
Linux 4.8-rc4
Tip revision: 3eab887
iommu-helper.c 
/*
 * IOMMU helper functions for the free area management
 */

#include <linux/export.h>
#include <linux/bitmap.h>
#include <linux/bug.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)) {
			start = ALIGN(shift + index, boundary_size) - shift;
			goto again;
		}
		bitmap_set(map, index, nr);
		return index;
	}
	return -1;
}
EXPORT_SYMBOL(iommu_area_alloc);
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