lib/ovs-atomic-pthreads.h

   1 /*
   2  * Copyright (c) 2013 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 /* This header implements atomic operation primitives using pthreads. */
  18 #ifndef IN_OVS_ATOMIC_H
  19 #error "This header should only be included indirectly via ovs-atomic.h."
  20 #endif
  21
  22 #define OVS_ATOMIC_PTHREADS_IMPL 1
  23
  24 #define DEFINE_PTHREAD_ATOMIC(TYPE, NAME)       \
  25     typedef struct {                            \
  26         TYPE value;                             \
  27         pthread_mutex_t mutex;                  \
  28     } NAME;
  29
  30 #define ATOMIC_BOOL_LOCK_FREE 0
  31 DEFINE_PTHREAD_ATOMIC(bool, atomic_bool);
  32
  33 #define ATOMIC_CHAR_LOCK_FREE 0
  34 DEFINE_PTHREAD_ATOMIC(char, atomic_char);
  35 DEFINE_PTHREAD_ATOMIC(signed char, atomic_schar);
  36 DEFINE_PTHREAD_ATOMIC(unsigned char, atomic_uchar);
  37
  38 #define ATOMIC_SHORT_LOCK_FREE 0
  39 DEFINE_PTHREAD_ATOMIC(short, atomic_short);
  40 DEFINE_PTHREAD_ATOMIC(unsigned short, atomic_ushort);
  41
  42 #define ATOMIC_INT_LOCK_FREE 0
  43 DEFINE_PTHREAD_ATOMIC(int, atomic_int);
  44 DEFINE_PTHREAD_ATOMIC(unsigned int, atomic_uint);
  45
  46 #define ATOMIC_LONG_LOCK_FREE 0
  47 DEFINE_PTHREAD_ATOMIC(long, atomic_long);
  48 DEFINE_PTHREAD_ATOMIC(unsigned long, atomic_ulong);
  49
  50 #define ATOMIC_LLONG_LOCK_FREE 0
  51 DEFINE_PTHREAD_ATOMIC(long long, atomic_llong);
  52 DEFINE_PTHREAD_ATOMIC(unsigned long long, atomic_ullong);
  53
  54 DEFINE_PTHREAD_ATOMIC(size_t, atomic_size_t);
  55 DEFINE_PTHREAD_ATOMIC(ptrdiff_t, atomic_ptrdiff_t);
  56
  57 DEFINE_PTHREAD_ATOMIC(intmax_t, atomic_intmax_t);
  58 DEFINE_PTHREAD_ATOMIC(uintmax_t, atomic_uintmax_t);
  59
  60 #define ATOMIC_POINTER_LOCK_FREE 0
  61 DEFINE_PTHREAD_ATOMIC(intptr_t, atomic_intptr_t);
  62 DEFINE_PTHREAD_ATOMIC(uintptr_t, atomic_uintptr_t);
  63
  64 /* Nonstandard atomic types. */
  65 DEFINE_PTHREAD_ATOMIC(uint8_t,  atomic_uint8_t);
  66 DEFINE_PTHREAD_ATOMIC(uint16_t, atomic_uint16_t);
  67 DEFINE_PTHREAD_ATOMIC(uint32_t, atomic_uint32_t);
  68 DEFINE_PTHREAD_ATOMIC(int8_t,   atomic_int8_t);
  69 DEFINE_PTHREAD_ATOMIC(int16_t,  atomic_int16_t);
  70 DEFINE_PTHREAD_ATOMIC(int32_t,  atomic_int32_t);
  71 DEFINE_PTHREAD_ATOMIC(uint64_t, atomic_uint64_t);
  72 DEFINE_PTHREAD_ATOMIC(int64_t,  atomic_int64_t);
  73
  74 typedef enum {
  75     memory_order_relaxed,
  76     memory_order_consume,
  77     memory_order_acquire,
  78     memory_order_release,
  79     memory_order_acq_rel,
  80     memory_order_seq_cst
  81 } memory_order;
  82
  83 #define ATOMIC_VAR_INIT(VALUE) { VALUE, PTHREAD_MUTEX_INITIALIZER }
  84 #define atomic_init(OBJECT, VALUE)                      \
  85     ((OBJECT)->value = (VALUE),                         \
  86      pthread_mutex_init(&(OBJECT)->mutex, NULL),        \
  87      (void) 0)
  88
  89 static inline void
  90 atomic_thread_fence(memory_order order OVS_UNUSED)
  91 {
  92     /* Nothing to do. */
  93 }
  94
  95 static inline void
  96 atomic_signal_fence(memory_order order OVS_UNUSED)
  97 {
  98     /* Nothing to do. */
  99 }
 100
 101 #define atomic_is_lock_free(OBJ) false
 102
 103 #define atomic_store(DST, SRC)                  \
 104     (pthread_mutex_lock(&(DST)->mutex),         \
 105      (DST)->value = (SRC),                      \
 106      pthread_mutex_unlock(&(DST)->mutex),       \
 107      (void) 0)
 108 #define atomic_store_explicit(DST, SRC, ORDER) \
 109     ((void) (ORDER), atomic_store(DST, SRC))
 110
 111 #define atomic_read(SRC, DST)                                           \
 112     (pthread_mutex_lock(CONST_CAST(pthread_mutex_t *, &(SRC)->mutex)),  \
 113      *(DST) = (SRC)->value,                                             \
 114      pthread_mutex_unlock(CONST_CAST(pthread_mutex_t *, &(SRC)->mutex)), \
 115      (void) 0)
 116 #define atomic_read_explicit(SRC, DST, ORDER)   \
 117     ((void) (ORDER), atomic_read(SRC, DST))
 118
 119 #define atomic_op__(RMW, OPERATOR, OPERAND, ORIG)       \
 120     (pthread_mutex_lock(&(RMW)->mutex),                 \
 121      *(ORIG) = (RMW)->value,                            \
 122      (RMW)->value OPERATOR (OPERAND),                   \
 123      pthread_mutex_unlock(&(RMW)->mutex),               \
 124      (void) 0)
 125
 126 #define atomic_add(RMW, OPERAND, ORIG) atomic_op__(RMW, +=, OPERAND, ORIG)
 127 #define atomic_sub(RMW, OPERAND, ORIG) atomic_op__(RMW, -=, OPERAND, ORIG)
 128 #define atomic_or( RMW, OPERAND, ORIG) atomic_op__(RMW, |=, OPERAND, ORIG)
 129 #define atomic_xor(RMW, OPERAND, ORIG) atomic_op__(RMW, ^=, OPERAND, ORIG)
 130 #define atomic_and(RMW, OPERAND, ORIG) atomic_op__(RMW, &=, OPERAND, ORIG)
 131
 132 #define atomic_add_explicit(RMW, OPERAND, ORIG, ORDER)  \
 133     ((void) (ORDER), atomic_add(RMW, OPERAND, ORIG))
 134 #define atomic_sub_explicit(RMW, OPERAND, ORIG, ORDER)  \
 135     ((void) (ORDER), atomic_sub(RMW, OPERAND, ORIG))
 136 #define atomic_or_explicit(RMW, OPERAND, ORIG, ORDER)   \
 137     ((void) (ORDER), atomic_or(RMW, OPERAND, ORIG))
 138 #define atomic_xor_explicit(RMW, OPERAND, ORIG, ORDER)  \
 139     ((void) (ORDER), atomic_xor(RMW, OPERAND, ORIG))
 140 #define atomic_and_explicit(RMW, OPERAND, ORIG, ORDER)  \
 141     ((void) (ORDER), atomic_and(RMW, OPERAND, ORIG))
 142 \f
 143 /* atomic_flag */
 144
 145 typedef struct {
 146     bool b;
 147     pthread_mutex_t mutex;
 148 } atomic_flag;
 149 #define ATOMIC_FLAG_INIT { false, PTHREAD_MUTEX_INITIALIZER }
 150
 151 bool atomic_flag_test_and_set(volatile atomic_flag *);
 152 bool atomic_flag_test_and_set_explicit(volatile atomic_flag *, memory_order);
 153
 154 void atomic_flag_clear(volatile atomic_flag *);
 155 void atomic_flag_clear_explicit(volatile atomic_flag *, memory_order);