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

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

include/linux/bitmap.h

+31 −5
Original line number Original line Diff line number Diff line
@@ -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); 




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,



extern 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);



/**

 * 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);

lib/bitmap.c

+13 −11
Original line number Original line Diff line number Diff line
@@ -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 @@ again: 
	}

	}

	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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