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linux-next/include/linux/bitmap.h
Reinette Chatre 01a3ee2b20 [PATCH] bitmap: parse input from kernel and user buffers 
lib/bitmap.c:bitmap_parse() is a library function that received as input a
user buffer.  This seemed to have originated from the way the write_proc
function of the /proc filesystem operates.

This has been reworked to not use kmalloc and eliminates a lot of
get_user() overhead by performing one access_ok before using __get_user().

We need to test if we are in kernel or user space (is_user) and access the
buffer differently.  We cannot use __get_user() to access kernel addresses
in all cases, for example in architectures with separate address space for
kernel and user.

This function will be useful for other uses as well; for example, taking
input for /sysfs instead of /proc, so it was changed to accept kernel
buffers.  We have this use for the Linux UWB project, as part as the
upcoming bandwidth allocator code.

Only a few routines used this function and they were changed too.

Signed-off-by: Reinette Chatre <reinette.chatre@linux.intel.com>
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Joe Korty <joe.korty@ccur.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11 11:14:22 -07:00

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#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:
*
* Note that nbits should be always a compile time evaluable constant.
* Otherwise many inlines will generate horrible code.
*
* 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(buf, buflen, dst, nbits) Parse bitmap dst from kernel buf
* bitmap_parse_user(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 *buf, unsigned int buflen, int is_user,
unsigned long *dst, int nbits);
extern int bitmap_parse_user(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)
{
if (nbits <= BITS_PER_LONG)
return hweight_long(*src & BITMAP_LAST_WORD_MASK(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);
}
static inline int bitmap_parse(const char *buf, unsigned int buflen,
unsigned long *maskp, int nmaskbits)
{
return __bitmap_parse(buf, buflen, 0, maskp, nmaskbits);
}
#endif /* __ASSEMBLY__ */
#endif /* __LINUX_BITMAP_H */
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