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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 /lib
parentc8475d144abb1e62958cc5ec281d2a9e161c1946 (diff)
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 'lib')
-rw-r--r--lib/bitmap.c24
1 files changed, 13 insertions, 11 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c
index b499ab6ada29..969ae8fbc85b 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -326,30 +326,32 @@ void bitmap_clear(unsigned long *map, unsigned int start, int len)
}
EXPORT_SYMBOL(bitmap_clear);
-/*
- * bitmap_find_next_zero_area - find a contiguous aligned zero area
+/**
+ * bitmap_find_next_zero_area_off - 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
+ * @align_offset: Alignment offset 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.
+ * the bit offset of all zero areas this function finds plus @align_offset
+ * is multiple of that power of 2.
*/
-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 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)
{
unsigned long index, end, i;
again:
index = find_next_zero_bit(map, size, start);
/* Align allocation */
- index = __ALIGN_MASK(index, align_mask);
+ index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
end = index + nr;
if (end > size)
@@ -361,7 +363,7 @@ again:
}
return index;
}
-EXPORT_SYMBOL(bitmap_find_next_zero_area);
+EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
/*
* Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,

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