iommu: export iommu_is_span_boundary helper function (3715863a) · Commits · 戴 / test

iommu_is_span_boundary is used internally in the IOMMU helper (lib/iommu-helper.c), a primitive function that judges whether a memory area spans LLD's segment boundary or not. It's difficult to convert some IOMMUs to use the IOMMU helper but iommu_is_span_boundary is still useful for them. So this patch exports it. This is needed for the parisc iommu fixes. Signed-off-by:

FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Kyle McMartin <kyle@parisc-linux.org> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Grant Grundler <grundler@parisc-linux.org> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

include/linux/iommu-helper.h

+3 −0

Original line number	Diff line number	Diff line
		extern int iommu_is_span_boundary(unsigned int index, unsigned int nr,
		unsigned long shift,
		unsigned long boundary_size);
		extern unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
		unsigned long start, unsigned int nr,
		unsigned long shift,

lib/iommu-helper.c

+6 −4

Original line number	Diff line number	Diff line
		@@ -40,10 +40,12 @@ static inline void set_bit_area(unsigned long *map, unsigned long i,
		}
		}

		static inline int is_span_boundary(unsigned int index, unsigned int nr,
		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;
		}
		@@ -57,7 +59,7 @@ unsigned long iommu_area_alloc(unsigned long *map, unsigned long size,
		again:
		index = find_next_zero_area(map, size, start, nr, align_mask);
		if (index != -1) {
		if (is_span_boundary(index, nr, shift, boundary_size)) {
		if (iommu_is_span_boundary(index, nr, shift, boundary_size)) {
		/* we could do more effectively */
		start = index + 1;
		goto again;

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