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>
diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c
index 495575a..a3b8d4c 100644
--- a/lib/iommu-helper.c
+++ b/lib/iommu-helper.c
@@ -40,10 +40,12 @@
}
}
-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 @@
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;