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iommu: export iommu_is_span_boundary helper function 

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>
This commit is contained in:
FUJITA Tomonori 2008-03-04 14:29:27 -08:00 committed by Linus Torvalds
parent 7eb701dc77
commit 3715863aa1
2 changed files with 9 additions and 4 deletions
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3
include/linux/iommu-helper.h
View File

@ -1,3 +1,6 @@
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,

10
lib/iommu-helper.c
View File

@ -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,
unsigned long shift,
unsigned long boundary_size)
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;