lib/ovs-atomic-locked.h

   1 /* This header implements atomic operation locking helpers. */
   2 #ifndef IN_OVS_ATOMIC_H
   3 #error "This header should only be included indirectly via ovs-atomic.h."
   4 #endif
   5
   6 #define OVS_ATOMIC_LOCKED_IMPL 1
   7
   8 void atomic_lock__(void *);
   9 void atomic_unlock__(void *);
  10
  11 #define atomic_store_locked(DST, SRC)           \
  12     (atomic_lock__(DST),                        \
  13      *(DST) = (SRC),                            \
  14      atomic_unlock__(DST),                      \
  15      (void) 0)
  16
  17 #define atomic_read_locked(SRC, DST)            \
  18     (atomic_lock__(SRC),                        \
  19      *(DST) = *(SRC),                           \
  20      atomic_unlock__(SRC),                      \
  21      (void) 0)
  22
  23 /* XXX: Evaluates EXP multiple times. */
  24 #define atomic_compare_exchange_locked(DST, EXP, SRC)   \
  25     (atomic_lock__(DST),                                \
  26      (*(DST) == *(EXP)                                  \
  27       ? (*(DST) = (SRC),                                \
  28          atomic_unlock__(DST),                          \
  29          true)                                          \
  30       : (*(EXP) = *(DST),                               \
  31          atomic_unlock__(DST),                          \
  32          false)))
  33
  34 #define atomic_op_locked_add +=
  35 #define atomic_op_locked_sub -=
  36 #define atomic_op_locked_or  |=
  37 #define atomic_op_locked_xor ^=
  38 #define atomic_op_locked_and &=
  39 #define atomic_op_locked(RMW, OP, OPERAND, ORIG)    \
  40     (atomic_lock__(RMW),                            \
  41      *(ORIG) = *(RMW),                              \
  42      *(RMW) atomic_op_locked_##OP (OPERAND),        \
  43      atomic_unlock__(RMW))