local.h 2.2 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556
  1. /* SPDX-License-Identifier: GPL-2.0 */
  2. #ifndef _ASM_GENERIC_LOCAL_H
  3. #define _ASM_GENERIC_LOCAL_H
  4. #include <linux/percpu.h>
  5. #include <linux/atomic.h>
  6. #include <asm/types.h>
  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 atomic_long_t. Which is
  12. * rather pointless. The whole point behind local_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. local_t allows exploitation of such capabilities.
  15. */
  16. /* Implement in terms of atomics. */
  17. /* Don't use typedef: don't want them to be mixed with atomic_t's. */
  18. typedef struct
  19. {
  20. atomic_long_t a;
  21. } local_t;
  22. #define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) }
  23. #define local_read(l) atomic_long_read(&(l)->a)
  24. #define local_set(l,i) atomic_long_set((&(l)->a),(i))
  25. #define local_inc(l) atomic_long_inc(&(l)->a)
  26. #define local_dec(l) atomic_long_dec(&(l)->a)
  27. #define local_add(i,l) atomic_long_add((i),(&(l)->a))
  28. #define local_sub(i,l) atomic_long_sub((i),(&(l)->a))
  29. #define local_sub_and_test(i, l) atomic_long_sub_and_test((i), (&(l)->a))
  30. #define local_dec_and_test(l) atomic_long_dec_and_test(&(l)->a)
  31. #define local_inc_and_test(l) atomic_long_inc_and_test(&(l)->a)
  32. #define local_add_negative(i, l) atomic_long_add_negative((i), (&(l)->a))
  33. #define local_add_return(i, l) atomic_long_add_return((i), (&(l)->a))
  34. #define local_sub_return(i, l) atomic_long_sub_return((i), (&(l)->a))
  35. #define local_inc_return(l) atomic_long_inc_return(&(l)->a)
  36. #define local_cmpxchg(l, o, n) atomic_long_cmpxchg((&(l)->a), (o), (n))
  37. #define local_xchg(l, n) atomic_long_xchg((&(l)->a), (n))
  38. #define local_add_unless(l, _a, u) atomic_long_add_unless((&(l)->a), (_a), (u))
  39. #define local_inc_not_zero(l) atomic_long_inc_not_zero(&(l)->a)
  40. /* Non-atomic variants, ie. preemption disabled and won't be touched
  41. * in interrupt, etc. Some archs can optimize this case well. */
  42. #define __local_inc(l) local_set((l), local_read(l) + 1)
  43. #define __local_dec(l) local_set((l), local_read(l) - 1)
  44. #define __local_add(i,l) local_set((l), local_read(l) + (i))
  45. #define __local_sub(i,l) local_set((l), local_read(l) - (i))
  46. #endif /* _ASM_GENERIC_LOCAL_H */