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c87a9f3a07
We've had these in the past and we need them again for the block allocator item bitmaps. Signed-off-by: Zach Brown <zab@versity.com>
102 lines
1.9 KiB
C
102 lines
1.9 KiB
C
#ifndef _BITOPS_H_
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#define _BITOPS_H_
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#include "sparse.h"
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/*
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* Implement little endian bitmaps in terms of native longs. __packed
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* is used to avoid unaligned accesses. These are neither atomic nor
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* particularly efficient.
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*/
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#define BITS_PER_LONG (sizeof(long) * 8)
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#if __BYTE_ORDER == __LITTLE_ENDIAN
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#define BITOP_LE_SWIZZLE 0
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#else
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#define BITOP_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7)
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#endif
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static inline unsigned long get_nr_word(int nr, void *addr)
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{
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unsigned long *longs = addr;
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unsigned long ind = nr / BITS_PER_LONG;
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unsigned long val;
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memcpy(&val, &longs[ind], sizeof(val));
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return val;
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}
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static inline void put_nr_word(int nr, void *addr, unsigned long val)
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{
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unsigned long *longs = addr;
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unsigned long ind = nr / BITS_PER_LONG;
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memcpy(&longs[ind], &val, sizeof(val));
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}
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static inline unsigned long nr_mask(int nr)
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{
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return 1UL << (nr % BITS_PER_LONG);
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}
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static inline int test_bit(int nr, void *addr)
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{
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unsigned long val = get_nr_word(nr, addr);
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return !!(val & nr_mask(nr));
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}
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static inline void set_bit(int nr, void *addr)
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{
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unsigned long val = get_nr_word(nr, addr);
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val |= nr_mask(nr);
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put_nr_word(nr, addr, val);
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}
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static inline void clear_bit(int nr, void *addr)
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{
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unsigned long val = get_nr_word(nr, addr);
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val &= ~nr_mask(nr);
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put_nr_word(nr, addr, val);
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}
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static inline int test_bit_le(int nr, void *addr)
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{
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return test_bit(nr ^ BITOP_LE_SWIZZLE, addr);
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}
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static inline int test_and_set_bit_le(int nr, void *addr)
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{
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int ret;
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nr ^= BITOP_LE_SWIZZLE;
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ret = test_bit(nr, addr);
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set_bit(nr, addr);
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return ret;
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}
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static inline void set_bit_le(int nr, void *addr)
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{
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set_bit(nr ^ BITOP_LE_SWIZZLE, addr);
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}
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static inline void clear_bit_le(int nr, void *addr)
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{
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clear_bit(nr ^ BITOP_LE_SWIZZLE, addr);
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}
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static inline int test_and_clear_bit_le(int nr, void *addr)
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{
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int ret;
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nr ^= BITOP_LE_SWIZZLE;
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ret = test_bit(nr, addr);
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clear_bit(nr, addr);
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return ret;
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}
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#endif
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