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authorLinus Torvalds <torvalds@linux-foundation.org>2009-12-16 10:06:39 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-16 10:06:39 -0800
commit9cfc86249f32d984339c6d1f8a1fd1326989b3b8 (patch)
tree56428d319483f54949de8d9d0a5b3f715287ed91 /lib/bitmap.c
parentfix ksm.h breakage of nommu build (diff)
parentgenalloc: use bitmap_find_next_zero_area (diff)
downloadlinux-dev-9cfc86249f32d984339c6d1f8a1fd1326989b3b8.tar.xz
linux-dev-9cfc86249f32d984339c6d1f8a1fd1326989b3b8.zip
Merge branch 'akpm'
* akpm: (173 commits) genalloc: use bitmap_find_next_zero_area ia64: use bitmap_find_next_zero_area sparc: use bitmap_find_next_zero_area mlx4: use bitmap_find_next_zero_area isp1362-hcd: use bitmap_find_next_zero_area iommu-helper: use bitmap library bitmap: introduce bitmap_set, bitmap_clear, bitmap_find_next_zero_area qnx4: use hweight8 qnx4fs: remove remains of the (defunct) write support resource: constify arg to resource_size() and resource_type() gru: send cross partition interrupts using the gru gru: function to generate chipset IPI values gru: update driver version number gru: improve GRU TLB dropin statistics gru: fix GRU interrupt race at deallocate gru: add hugepage support gru: fix bug in allocation of kernel contexts gru: update GRU structures to match latest hardware spec gru: check for correct GRU chiplet assignment gru: remove stray local_irq_enable ...
Diffstat (limited to 'lib/bitmap.c')
-rw-r--r--lib/bitmap.c81
1 files changed, 81 insertions, 0 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 702565821c99..11bf49750583 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -271,6 +271,87 @@ int __bitmap_weight(const unsigned long *bitmap, int bits)
}
EXPORT_SYMBOL(__bitmap_weight);
+#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) % BITS_PER_LONG))
+
+void bitmap_set(unsigned long *map, int start, int nr)
+{
+ unsigned long *p = map + BIT_WORD(start);
+ const int size = start + nr;
+ int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
+ unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
+
+ while (nr - bits_to_set >= 0) {
+ *p |= mask_to_set;
+ nr -= bits_to_set;
+ bits_to_set = BITS_PER_LONG;
+ mask_to_set = ~0UL;
+ p++;
+ }
+ if (nr) {
+ mask_to_set &= BITMAP_LAST_WORD_MASK(size);
+ *p |= mask_to_set;
+ }
+}
+EXPORT_SYMBOL(bitmap_set);
+
+void bitmap_clear(unsigned long *map, int start, int nr)
+{
+ unsigned long *p = map + BIT_WORD(start);
+ const int size = start + nr;
+ int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
+ unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
+
+ while (nr - bits_to_clear >= 0) {
+ *p &= ~mask_to_clear;
+ nr -= bits_to_clear;
+ bits_to_clear = BITS_PER_LONG;
+ mask_to_clear = ~0UL;
+ p++;
+ }
+ if (nr) {
+ mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
+ *p &= ~mask_to_clear;
+ }
+}
+EXPORT_SYMBOL(bitmap_clear);
+
+/*
+ * bitmap_find_next_zero_area - find a contiguous aligned zero area
+ * @map: The address to base the search on
+ * @size: The bitmap size in bits
+ * @start: The bitnumber to start searching at
+ * @nr: The number of zeroed bits we're looking for
+ * @align_mask: Alignment mask for zero area
+ *
+ * The @align_mask should be one less than a power of 2; the effect is that
+ * the bit offset of all zero areas this function finds is multiples of that
+ * power of 2. A @align_mask of 0 means no alignment is required.
+ */
+unsigned long bitmap_find_next_zero_area(unsigned long *map,
+ unsigned long size,
+ unsigned long start,
+ unsigned int nr,
+ unsigned long align_mask)
+{
+ unsigned long index, end, i;
+again:
+ index = find_next_zero_bit(map, size, start);
+
+ /* Align allocation */
+ index = __ALIGN_MASK(index, align_mask);
+
+ end = index + nr;
+ if (end > size)
+ return end;
+ i = find_next_bit(map, end, index);
+ if (i < end) {
+ start = i + 1;
+ goto again;
+ }
+ return index;
+}
+EXPORT_SYMBOL(bitmap_find_next_zero_area);
+
/*
* Bitmap printing & parsing functions: first version by Bill Irwin,
* second version by Paul Jackson, third by Joe Korty.