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authorMichal Nazarewicz <mina86@mina86.com>2014-12-12 16:54:45 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-12-13 12:42:46 -0800
commit5e19b013f55a884c59a14391b22138899d1cc4cc (patch)
tree9bf703aa3539ddf0e2b9767787f112d04559ed84 /include
parentc8475d144abb1e62958cc5ec281d2a9e161c1946 (diff)
downloadlinux-5e19b013f55a884c59a14391b22138899d1cc4cc.tar.bz2
lib: bitmap: add alignment offset for bitmap_find_next_zero_area()
Add a bitmap_find_next_zero_area_off() function which works like bitmap_find_next_zero_area() function except it allows an offset to be specified when alignment is checked. This lets caller request a bit such that its number plus the offset is aligned according to the mask. [gregory.0xf0@gmail.com: Retrieved from https://patchwork.linuxtv.org/patch/6254/ and updated documentation] Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Gregory Fong <gregory.0xf0@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Laura Abbott <lauraa@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/bitmap.h36
1 files changed, 31 insertions, 5 deletions
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index e1c8d080c427..34e020c23644 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -45,6 +45,7 @@
* bitmap_set(dst, pos, nbits) Set specified bit area
* bitmap_clear(dst, pos, nbits) Clear specified bit area
* bitmap_find_next_zero_area(buf, len, pos, n, mask) Find bit free area
+ * bitmap_find_next_zero_area_off(buf, len, pos, n, mask) as above
* bitmap_shift_right(dst, src, n, nbits) *dst = *src >> n
* bitmap_shift_left(dst, src, n, nbits) *dst = *src << n
* bitmap_remap(dst, src, old, new, nbits) *dst = map(old, new)(src)
@@ -114,11 +115,36 @@ extern int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);
extern void bitmap_set(unsigned long *map, unsigned int start, int len);
extern void bitmap_clear(unsigned long *map, unsigned int start, int len);
-extern unsigned long bitmap_find_next_zero_area(unsigned long *map,
- unsigned long size,
- unsigned long start,
- unsigned int nr,
- unsigned long align_mask);
+
+extern unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
+ unsigned long size,
+ unsigned long start,
+ unsigned int nr,
+ unsigned long align_mask,
+ unsigned long align_offset);
+
+/**
+ * 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.
+ */
+static inline unsigned long
+bitmap_find_next_zero_area(unsigned long *map,
+ unsigned long size,
+ unsigned long start,
+ unsigned int nr,
+ unsigned long align_mask)
+{
+ return bitmap_find_next_zero_area_off(map, size, start, nr,
+ align_mask, 0);
+}
extern int bitmap_scnprintf(char *buf, unsigned int len,
const unsigned long *src, int nbits);