Commit 5e19b013 authored by Michal Nazarewicz's avatar Michal Nazarewicz Committed by Linus Torvalds

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: default avatarMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: default avatarKyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarGregory 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c8475d14
...@@ -45,6 +45,7 @@ ...@@ -45,6 +45,7 @@
* bitmap_set(dst, pos, nbits) Set specified bit area * bitmap_set(dst, pos, nbits) Set specified bit area
* bitmap_clear(dst, pos, nbits) Clear 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(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_right(dst, src, n, nbits) *dst = *src >> n
* bitmap_shift_left(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) * 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); ...@@ -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_set(unsigned long *map, unsigned int start, int len);
extern void bitmap_clear(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, extern unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
unsigned long start, unsigned long size,
unsigned int nr, unsigned long start,
unsigned long align_mask); 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, extern int bitmap_scnprintf(char *buf, unsigned int len,
const unsigned long *src, int nbits); const unsigned long *src, int nbits);
......
...@@ -326,30 +326,32 @@ void bitmap_clear(unsigned long *map, unsigned int start, int len) ...@@ -326,30 +326,32 @@ void bitmap_clear(unsigned long *map, unsigned int start, int len)
} }
EXPORT_SYMBOL(bitmap_clear); 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 * @map: The address to base the search on
* @size: The bitmap size in bits * @size: The bitmap size in bits
* @start: The bitnumber to start searching at * @start: The bitnumber to start searching at
* @nr: The number of zeroed bits we're looking for * @nr: The number of zeroed bits we're looking for
* @align_mask: Alignment mask for zero area * @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 @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 * the bit offset of all zero areas this function finds plus @align_offset
* power of 2. A @align_mask of 0 means no alignment is required. * is multiple of that power of 2.
*/ */
unsigned long bitmap_find_next_zero_area(unsigned long *map, unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
unsigned long size, unsigned long size,
unsigned long start, unsigned long start,
unsigned int nr, unsigned int nr,
unsigned long align_mask) unsigned long align_mask,
unsigned long align_offset)
{ {
unsigned long index, end, i; unsigned long index, end, i;
again: again:
index = find_next_zero_bit(map, size, start); index = find_next_zero_bit(map, size, start);
/* Align allocation */ /* Align allocation */
index = __ALIGN_MASK(index, align_mask); index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
end = index + nr; end = index + nr;
if (end > size) if (end > size)
...@@ -361,7 +363,7 @@ unsigned long bitmap_find_next_zero_area(unsigned long *map, ...@@ -361,7 +363,7 @@ unsigned long bitmap_find_next_zero_area(unsigned long *map,
} }
return index; 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, * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
......
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