linux/include/asm-generic/local64.h
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   1#ifndef _ASM_GENERIC_LOCAL64_H
   2#define _ASM_GENERIC_LOCAL64_H
   3
   4#include <linux/percpu.h>
   5#include <asm/types.h>
   6
   7/*
   8 * A signed long type for operations which are atomic for a single CPU.
   9 * Usually used in combination with per-cpu variables.
  10 *
  11 * This is the default implementation, which uses atomic64_t.  Which is
  12 * rather pointless.  The whole point behind local64_t is that some processors
  13 * can perform atomic adds and subtracts in a manner which is atomic wrt IRQs
  14 * running on this CPU.  local64_t allows exploitation of such capabilities.
  15 */
  16
  17/* Implement in terms of atomics. */
  18
  19#if BITS_PER_LONG == 64
  20
  21#include <asm/local.h>
  22
  23typedef struct {
  24        local_t a;
  25} local64_t;
  26
  27#define LOCAL64_INIT(i) { LOCAL_INIT(i) }
  28
  29#define local64_read(l)         local_read(&(l)->a)
  30#define local64_set(l,i)        local_set((&(l)->a),(i))
  31#define local64_inc(l)          local_inc(&(l)->a)
  32#define local64_dec(l)          local_dec(&(l)->a)
  33#define local64_add(i,l)        local_add((i),(&(l)->a))
  34#define local64_sub(i,l)        local_sub((i),(&(l)->a))
  35
  36#define local64_sub_and_test(i, l) local_sub_and_test((i), (&(l)->a))
  37#define local64_dec_and_test(l) local_dec_and_test(&(l)->a)
  38#define local64_inc_and_test(l) local_inc_and_test(&(l)->a)
  39#define local64_add_negative(i, l) local_add_negative((i), (&(l)->a))
  40#define local64_add_return(i, l) local_add_return((i), (&(l)->a))
  41#define local64_sub_return(i, l) local_sub_return((i), (&(l)->a))
  42#define local64_inc_return(l)   local_inc_return(&(l)->a)
  43
  44#define local64_cmpxchg(l, o, n) local_cmpxchg((&(l)->a), (o), (n))
  45#define local64_xchg(l, n)      local_xchg((&(l)->a), (n))
  46#define local64_add_unless(l, _a, u) local_add_unless((&(l)->a), (_a), (u))
  47#define local64_inc_not_zero(l) local_inc_not_zero(&(l)->a)
  48
  49/* Non-atomic variants, ie. preemption disabled and won't be touched
  50 * in interrupt, etc.  Some archs can optimize this case well. */
  51#define __local64_inc(l)        local64_set((l), local64_read(l) + 1)
  52#define __local64_dec(l)        local64_set((l), local64_read(l) - 1)
  53#define __local64_add(i,l)      local64_set((l), local64_read(l) + (i))
  54#define __local64_sub(i,l)      local64_set((l), local64_read(l) - (i))
  55
  56#else /* BITS_PER_LONG != 64 */
  57
  58#include <linux/atomic.h>
  59
  60/* Don't use typedef: don't want them to be mixed with atomic_t's. */
  61typedef struct {
  62        atomic64_t a;
  63} local64_t;
  64
  65#define LOCAL64_INIT(i) { ATOMIC_LONG_INIT(i) }
  66
  67#define local64_read(l)         atomic64_read(&(l)->a)
  68#define local64_set(l,i)        atomic64_set((&(l)->a),(i))
  69#define local64_inc(l)          atomic64_inc(&(l)->a)
  70#define local64_dec(l)          atomic64_dec(&(l)->a)
  71#define local64_add(i,l)        atomic64_add((i),(&(l)->a))
  72#define local64_sub(i,l)        atomic64_sub((i),(&(l)->a))
  73
  74#define local64_sub_and_test(i, l) atomic64_sub_and_test((i), (&(l)->a))
  75#define local64_dec_and_test(l) atomic64_dec_and_test(&(l)->a)
  76#define local64_inc_and_test(l) atomic64_inc_and_test(&(l)->a)
  77#define local64_add_negative(i, l) atomic64_add_negative((i), (&(l)->a))
  78#define local64_add_return(i, l) atomic64_add_return((i), (&(l)->a))
  79#define local64_sub_return(i, l) atomic64_sub_return((i), (&(l)->a))
  80#define local64_inc_return(l)   atomic64_inc_return(&(l)->a)
  81
  82#define local64_cmpxchg(l, o, n) atomic64_cmpxchg((&(l)->a), (o), (n))
  83#define local64_xchg(l, n)      atomic64_xchg((&(l)->a), (n))
  84#define local64_add_unless(l, _a, u) atomic64_add_unless((&(l)->a), (_a), (u))
  85#define local64_inc_not_zero(l) atomic64_inc_not_zero(&(l)->a)
  86
  87/* Non-atomic variants, ie. preemption disabled and won't be touched
  88 * in interrupt, etc.  Some archs can optimize this case well. */
  89#define __local64_inc(l)        local64_set((l), local64_read(l) + 1)
  90#define __local64_dec(l)        local64_set((l), local64_read(l) - 1)
  91#define __local64_add(i,l)      local64_set((l), local64_read(l) + (i))
  92#define __local64_sub(i,l)      local64_set((l), local64_read(l) - (i))
  93
  94#endif /* BITS_PER_LONG != 64 */
  95
  96#endif /* _ASM_GENERIC_LOCAL64_H */
  97
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