/* SPDX-License-Identifier: GPL-2.0 */
  #ifndef _ASM_GENERIC_LOCAL_H
  #define _ASM_GENERIC_LOCAL_H
  
  #include <linux/percpu.h>
  #include <linux/atomic.h>
  #include <asm/types.h>
  
  /*
   * A signed long type for operations which are atomic for a single CPU.
   * Usually used in combination with per-cpu variables.
   *
   * This is the default implementation, which uses atomic_long_t.  Which is
   * rather pointless.  The whole point behind local_t is that some processors
   * can perform atomic adds and subtracts in a manner which is atomic wrt IRQs
   * running on this CPU.  local_t allows exploitation of such capabilities.
   */
  
  /* Implement in terms of atomics. */
  
  /* Don't use typedef: don't want them to be mixed with atomic_t's. */
  typedef struct
  {
  	atomic_long_t a;
  } local_t;
  
  #define LOCAL_INIT(i)	{ ATOMIC_LONG_INIT(i) }
  
  #define local_read(l)	atomic_long_read(&(l)->a)
  #define local_set(l,i)	atomic_long_set((&(l)->a),(i))
  #define local_inc(l)	atomic_long_inc(&(l)->a)
  #define local_dec(l)	atomic_long_dec(&(l)->a)
  #define local_add(i,l)	atomic_long_add((i),(&(l)->a))
  #define local_sub(i,l)	atomic_long_sub((i),(&(l)->a))
  
  #define local_sub_and_test(i, l) atomic_long_sub_and_test((i), (&(l)->a))
  #define local_dec_and_test(l) atomic_long_dec_and_test(&(l)->a)
  #define local_inc_and_test(l) atomic_long_inc_and_test(&(l)->a)
  #define local_add_negative(i, l) atomic_long_add_negative((i), (&(l)->a))
  #define local_add_return(i, l) atomic_long_add_return((i), (&(l)->a))
  #define local_sub_return(i, l) atomic_long_sub_return((i), (&(l)->a))
  #define local_inc_return(l) atomic_long_inc_return(&(l)->a)
  
  #define local_cmpxchg(l, o, n) atomic_long_cmpxchg((&(l)->a), (o), (n))
  #define local_xchg(l, n) atomic_long_xchg((&(l)->a), (n))
  #define local_add_unless(l, _a, u) atomic_long_add_unless((&(l)->a), (_a), (u))
  #define local_inc_not_zero(l) atomic_long_inc_not_zero(&(l)->a)
  
  /* Non-atomic variants, ie. preemption disabled and won't be touched
   * in interrupt, etc.  Some archs can optimize this case well. */
  #define __local_inc(l)		local_set((l), local_read(l) + 1)
  #define __local_dec(l)		local_set((l), local_read(l) - 1)
  #define __local_add(i,l)	local_set((l), local_read(l) + (i))
  #define __local_sub(i,l)	local_set((l), local_read(l) - (i))
  
  #endif /* _ASM_GENERIC_LOCAL_H */