linux-stable/include/linux/bitmap.h
Paul Jackson 87e2480258 [PATCH] bitmap: region cleanup
Paul Mundt <lethal@linux-sh.org> says:

This patch set implements a number of patches to clean up and restructure the
bitmap region code, in addition to extending the interface to support
multiword spanning allocations.

The current implementation (before this patch set) is limited by only being
able to allocate pages <= BITS_PER_LONG, as noted by the strategically
positioned BUG_ON() at lib/bitmap.c:752:

        /* We don't do regions of pages > BITS_PER_LONG.  The
	 * algorithm would be a simple look for multiple zeros in the
	 * array, but there's no driver today that needs this.  If you
	 * trip this BUG(), you get to code it... */
        BUG_ON(pages > BITS_PER_LONG);

As I seem to have been the first person to trigger this, the result ends up
being the following patch set with the help of Paul Jackson.

The final patch in the series eliminates quite a bit of code duplication, so
the bitmap code size ends up being smaller than the current implementation as
an added bonus.

After these are applied, it should already be possible to do multiword
allocations with dma_alloc_coherent() out of ranges established by
dma_declare_coherent_memory() on x86 without having to change any of the code,
and the SH store queue API will follow up on this as the other user that needs
support for this.

This patch:

Some code cleanup on the lib/bitmap.c bitmap_*_region() routines:

 * spacing
 * variable names
 * comments

Has no change to code function.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-24 07:33:20 -08:00

270 lines
9 KiB
C

#ifndef __LINUX_BITMAP_H
#define __LINUX_BITMAP_H
#ifndef __ASSEMBLY__
#include <linux/types.h>
#include <linux/bitops.h>
#include <linux/string.h>
/*
* bitmaps provide bit arrays that consume one or more unsigned
* longs. The bitmap interface and available operations are listed
* here, in bitmap.h
*
* Function implementations generic to all architectures are in
* lib/bitmap.c. Functions implementations that are architecture
* specific are in various include/asm-<arch>/bitops.h headers
* and other arch/<arch> specific files.
*
* See lib/bitmap.c for more details.
*/
/*
* The available bitmap operations and their rough meaning in the
* case that the bitmap is a single unsigned long are thus:
*
* bitmap_zero(dst, nbits) *dst = 0UL
* bitmap_fill(dst, nbits) *dst = ~0UL
* bitmap_copy(dst, src, nbits) *dst = *src
* bitmap_and(dst, src1, src2, nbits) *dst = *src1 & *src2
* bitmap_or(dst, src1, src2, nbits) *dst = *src1 | *src2
* bitmap_xor(dst, src1, src2, nbits) *dst = *src1 ^ *src2
* bitmap_andnot(dst, src1, src2, nbits) *dst = *src1 & ~(*src2)
* bitmap_complement(dst, src, nbits) *dst = ~(*src)
* bitmap_equal(src1, src2, nbits) Are *src1 and *src2 equal?
* bitmap_intersects(src1, src2, nbits) Do *src1 and *src2 overlap?
* bitmap_subset(src1, src2, nbits) Is *src1 a subset of *src2?
* bitmap_empty(src, nbits) Are all bits zero in *src?
* bitmap_full(src, nbits) Are all bits set in *src?
* bitmap_weight(src, nbits) Hamming Weight: number set bits
* 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)
* bitmap_bitremap(oldbit, old, new, nbits) newbit = map(old, new)(oldbit)
* bitmap_scnprintf(buf, len, src, nbits) Print bitmap src to buf
* bitmap_parse(ubuf, ulen, dst, nbits) Parse bitmap dst from user buf
* bitmap_scnlistprintf(buf, len, src, nbits) Print bitmap src as list to buf
* bitmap_parselist(buf, dst, nbits) Parse bitmap dst from list
* bitmap_find_free_region(bitmap, bits, order) Find and allocate bit region
* bitmap_release_region(bitmap, pos, order) Free specified bit region
* bitmap_allocate_region(bitmap, pos, order) Allocate specified bit region
*/
/*
* Also the following operations in asm/bitops.h apply to bitmaps.
*
* set_bit(bit, addr) *addr |= bit
* clear_bit(bit, addr) *addr &= ~bit
* change_bit(bit, addr) *addr ^= bit
* test_bit(bit, addr) Is bit set in *addr?
* test_and_set_bit(bit, addr) Set bit and return old value
* test_and_clear_bit(bit, addr) Clear bit and return old value
* test_and_change_bit(bit, addr) Change bit and return old value
* find_first_zero_bit(addr, nbits) Position first zero bit in *addr
* find_first_bit(addr, nbits) Position first set bit in *addr
* find_next_zero_bit(addr, nbits, bit) Position next zero bit in *addr >= bit
* find_next_bit(addr, nbits, bit) Position next set bit in *addr >= bit
*/
/*
* The DECLARE_BITMAP(name,bits) macro, in linux/types.h, can be used
* to declare an array named 'name' of just enough unsigned longs to
* contain all bit positions from 0 to 'bits' - 1.
*/
/*
* lib/bitmap.c provides these functions:
*/
extern int __bitmap_empty(const unsigned long *bitmap, int bits);
extern int __bitmap_full(const unsigned long *bitmap, int bits);
extern int __bitmap_equal(const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits);
extern void __bitmap_complement(unsigned long *dst, const unsigned long *src,
int bits);
extern void __bitmap_shift_right(unsigned long *dst,
const unsigned long *src, int shift, int bits);
extern void __bitmap_shift_left(unsigned long *dst,
const unsigned long *src, int shift, int bits);
extern void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits);
extern void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits);
extern void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits);
extern void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits);
extern int __bitmap_intersects(const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits);
extern int __bitmap_subset(const unsigned long *bitmap1,
const unsigned long *bitmap2, int bits);
extern int __bitmap_weight(const unsigned long *bitmap, int bits);
extern int bitmap_scnprintf(char *buf, unsigned int len,
const unsigned long *src, int nbits);
extern int bitmap_parse(const char __user *ubuf, unsigned int ulen,
unsigned long *dst, int nbits);
extern int bitmap_scnlistprintf(char *buf, unsigned int len,
const unsigned long *src, int nbits);
extern int bitmap_parselist(const char *buf, unsigned long *maskp,
int nmaskbits);
extern void bitmap_remap(unsigned long *dst, const unsigned long *src,
const unsigned long *old, const unsigned long *new, int bits);
extern int bitmap_bitremap(int oldbit,
const unsigned long *old, const unsigned long *new, int bits);
extern int bitmap_find_free_region(unsigned long *bitmap, int bits, int order);
extern void bitmap_release_region(unsigned long *bitmap, int pos, int order);
extern int bitmap_allocate_region(unsigned long *bitmap, int pos, int order);
#define BITMAP_LAST_WORD_MASK(nbits) \
( \
((nbits) % BITS_PER_LONG) ? \
(1UL<<((nbits) % BITS_PER_LONG))-1 : ~0UL \
)
static inline void bitmap_zero(unsigned long *dst, int nbits)
{
if (nbits <= BITS_PER_LONG)
*dst = 0UL;
else {
int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
memset(dst, 0, len);
}
}
static inline void bitmap_fill(unsigned long *dst, int nbits)
{
size_t nlongs = BITS_TO_LONGS(nbits);
if (nlongs > 1) {
int len = (nlongs - 1) * sizeof(unsigned long);
memset(dst, 0xff, len);
}
dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
}
static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
int nbits)
{
if (nbits <= BITS_PER_LONG)
*dst = *src;
else {
int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
memcpy(dst, src, len);
}
}
static inline void bitmap_and(unsigned long *dst, const unsigned long *src1,
const unsigned long *src2, int nbits)
{
if (nbits <= BITS_PER_LONG)
*dst = *src1 & *src2;
else
__bitmap_and(dst, src1, src2, nbits);
}
static inline void bitmap_or(unsigned long *dst, const unsigned long *src1,
const unsigned long *src2, int nbits)
{
if (nbits <= BITS_PER_LONG)
*dst = *src1 | *src2;
else
__bitmap_or(dst, src1, src2, nbits);
}
static inline void bitmap_xor(unsigned long *dst, const unsigned long *src1,
const unsigned long *src2, int nbits)
{
if (nbits <= BITS_PER_LONG)
*dst = *src1 ^ *src2;
else
__bitmap_xor(dst, src1, src2, nbits);
}
static inline void bitmap_andnot(unsigned long *dst, const unsigned long *src1,
const unsigned long *src2, int nbits)
{
if (nbits <= BITS_PER_LONG)
*dst = *src1 & ~(*src2);
else
__bitmap_andnot(dst, src1, src2, nbits);
}
static inline void bitmap_complement(unsigned long *dst, const unsigned long *src,
int nbits)
{
if (nbits <= BITS_PER_LONG)
*dst = ~(*src) & BITMAP_LAST_WORD_MASK(nbits);
else
__bitmap_complement(dst, src, nbits);
}
static inline int bitmap_equal(const unsigned long *src1,
const unsigned long *src2, int nbits)
{
if (nbits <= BITS_PER_LONG)
return ! ((*src1 ^ *src2) & BITMAP_LAST_WORD_MASK(nbits));
else
return __bitmap_equal(src1, src2, nbits);
}
static inline int bitmap_intersects(const unsigned long *src1,
const unsigned long *src2, int nbits)
{
if (nbits <= BITS_PER_LONG)
return ((*src1 & *src2) & BITMAP_LAST_WORD_MASK(nbits)) != 0;
else
return __bitmap_intersects(src1, src2, nbits);
}
static inline int bitmap_subset(const unsigned long *src1,
const unsigned long *src2, int nbits)
{
if (nbits <= BITS_PER_LONG)
return ! ((*src1 & ~(*src2)) & BITMAP_LAST_WORD_MASK(nbits));
else
return __bitmap_subset(src1, src2, nbits);
}
static inline int bitmap_empty(const unsigned long *src, int nbits)
{
if (nbits <= BITS_PER_LONG)
return ! (*src & BITMAP_LAST_WORD_MASK(nbits));
else
return __bitmap_empty(src, nbits);
}
static inline int bitmap_full(const unsigned long *src, int nbits)
{
if (nbits <= BITS_PER_LONG)
return ! (~(*src) & BITMAP_LAST_WORD_MASK(nbits));
else
return __bitmap_full(src, nbits);
}
static inline int bitmap_weight(const unsigned long *src, int nbits)
{
return __bitmap_weight(src, nbits);
}
static inline void bitmap_shift_right(unsigned long *dst,
const unsigned long *src, int n, int nbits)
{
if (nbits <= BITS_PER_LONG)
*dst = *src >> n;
else
__bitmap_shift_right(dst, src, n, nbits);
}
static inline void bitmap_shift_left(unsigned long *dst,
const unsigned long *src, int n, int nbits)
{
if (nbits <= BITS_PER_LONG)
*dst = (*src << n) & BITMAP_LAST_WORD_MASK(nbits);
else
__bitmap_shift_left(dst, src, n, nbits);
}
#endif /* __ASSEMBLY__ */
#endif /* __LINUX_BITMAP_H */