fixed coding style
[sliver-openvswitch.git] / lib / ovs-thread.h
index 98428fd..7f3195d 100644 (file)
 #include "ovs-atomic.h"
 #include "util.h"
 
-/* glibc has some non-portable mutex types and initializers:
- *
- *    - PTHREAD_MUTEX_ADAPTIVE_NP is a mutex type that works as a spinlock that
- *      falls back to a mutex after spinning for some number of iterations.
- *
- *    - PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP is a non-portable initializer
- *      for an error-checking mutex.
- *
- * We use these definitions to fall back to PTHREAD_MUTEX_NORMAL instead in
- * these cases.
- *
- * (glibc has other non-portable initializers, but we can't reasonably
- * substitute for them here.) */
-#ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
-#define PTHREAD_MUTEX_ADAPTIVE PTHREAD_MUTEX_ADAPTIVE_NP
-#define PTHREAD_ADAPTIVE_MUTEX_INITIALIZER \
-    PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
-#else
-#define PTHREAD_MUTEX_ADAPTIVE PTHREAD_MUTEX_NORMAL
-#define PTHREAD_ADAPTIVE_MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
-#endif
 
+/* Mutex. */
+struct OVS_LOCKABLE ovs_mutex {
+    pthread_mutex_t lock;
+    const char *where;
+};
+
+/* "struct ovs_mutex" initializer. */
 #ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
-#define PTHREAD_ERRORCHECK_MUTEX_INITIALIZER \
-    PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
+#define OVS_MUTEX_INITIALIZER { PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP, NULL }
 #else
-#define PTHREAD_ERRORCHECK_MUTEX_INITIALIZER PTHREAD_MUTEX_INITIALIZER
+#define OVS_MUTEX_INITIALIZER { PTHREAD_MUTEX_INITIALIZER, NULL }
 #endif
-\f
-/* Simple wrappers for pthreads functions.  Most of these functions abort the
- * process with an error message on any error.  The *_trylock() functions are
- * exceptions: they pass through a 0 or EBUSY return value to the caller and
- * abort on any other error. */
 
-void xpthread_mutex_init(pthread_mutex_t *, pthread_mutexattr_t *);
-void xpthread_mutex_destroy(pthread_mutex_t *);
-void xpthread_mutex_lock(pthread_mutex_t *mutex) OVS_ACQUIRES(mutex);
-void xpthread_mutex_unlock(pthread_mutex_t *mutex) OVS_RELEASES(mutex);
-int xpthread_mutex_trylock(pthread_mutex_t *);
+/* ovs_mutex functions analogous to pthread_mutex_*() functions.
+ *
+ * Most of these functions abort the process with an error message on any
+ * error.  ovs_mutex_trylock() is an exception: it passes through a 0 or EBUSY
+ * return value to the caller and aborts on any other error. */
+void ovs_mutex_init(const struct ovs_mutex *);
+void ovs_mutex_init_recursive(const struct ovs_mutex *);
+void ovs_mutex_destroy(const struct ovs_mutex *);
+void ovs_mutex_unlock(const struct ovs_mutex *mutex) OVS_RELEASES(mutex);
+void ovs_mutex_lock_at(const struct ovs_mutex *mutex, const char *where)
+    OVS_ACQUIRES(mutex);
+#define ovs_mutex_lock(mutex) \
+        ovs_mutex_lock_at(mutex, SOURCE_LOCATOR)
+
+int ovs_mutex_trylock_at(const struct ovs_mutex *mutex, const char *where)
+    OVS_TRY_LOCK(0, mutex);
+#define ovs_mutex_trylock(mutex) \
+        ovs_mutex_trylock_at(mutex, SOURCE_LOCATOR)
+
+void ovs_mutex_cond_wait(pthread_cond_t *, const struct ovs_mutex *);
 
+/* Wrappers for pthread_mutex_*() that abort the process on any error.
+ * This is still needed when ovs-atomic-pthreads.h is used. */
+void xpthread_mutex_lock(pthread_mutex_t *mutex);
+void xpthread_mutex_unlock(pthread_mutex_t *mutex);
+
+/* Wrappers for pthread_mutexattr_*() that abort the process on any error. */
 void xpthread_mutexattr_init(pthread_mutexattr_t *);
 void xpthread_mutexattr_destroy(pthread_mutexattr_t *);
 void xpthread_mutexattr_settype(pthread_mutexattr_t *, int type);
 void xpthread_mutexattr_gettype(pthread_mutexattr_t *, int *typep);
 
-void xpthread_rwlock_init(pthread_rwlock_t *, pthread_rwlockattr_t *);
-void xpthread_rwlock_destroy(pthread_rwlock_t *);
-void xpthread_rwlock_rdlock(pthread_rwlock_t *rwlock) OVS_ACQUIRES(rwlock);
-void xpthread_rwlock_wrlock(pthread_rwlock_t *rwlock) OVS_ACQUIRES(rwlock);
-void xpthread_rwlock_unlock(pthread_rwlock_t *rwlock) OVS_RELEASES(rwlock);
-int xpthread_rwlock_tryrdlock(pthread_rwlock_t *);
-int xpthread_rwlock_trywrlock(pthread_rwlock_t *);
+/* Read-write lock. */
+struct OVS_LOCKABLE ovs_rwlock {
+    pthread_rwlock_t lock;
+    const char *where;
+};
+
+/* Initializer. */
+#define OVS_RWLOCK_INITIALIZER { PTHREAD_RWLOCK_INITIALIZER, NULL }
+
+/* ovs_rwlock functions analogous to pthread_rwlock_*() functions.
+ *
+ * Most of these functions abort the process with an error message on any
+ * error.  The "trylock" functions are exception: they pass through a 0 or
+ * EBUSY return value to the caller and abort on any other error. */
+void ovs_rwlock_init(const struct ovs_rwlock *);
+void ovs_rwlock_destroy(const struct ovs_rwlock *);
+void ovs_rwlock_unlock(const struct ovs_rwlock *rwlock) OVS_RELEASES(rwlock);
+
+void ovs_rwlock_wrlock_at(const struct ovs_rwlock *rwlock, const char *where)
+    OVS_ACQ_WRLOCK(rwlock);
+#define ovs_rwlock_wrlock(rwlock) \
+        ovs_rwlock_wrlock_at(rwlock, SOURCE_LOCATOR)
 
+int ovs_rwlock_trywrlock_at(const struct ovs_rwlock *rwlock, const char *where)
+    OVS_TRY_WRLOCK(0, rwlock);
+#define ovs_rwlock_trywrlock(rwlock) \
+    ovs_rwlock_trywrlock_at(rwlock, SOURCE_LOCATOR)
+
+void ovs_rwlock_rdlock_at(const struct ovs_rwlock *rwlock, const char *where)
+    OVS_ACQ_RDLOCK(rwlock);
+#define ovs_rwlock_rdlock(rwlock) \
+        ovs_rwlock_rdlock_at(rwlock, SOURCE_LOCATOR)
+
+int ovs_rwlock_tryrdlock_at(const struct ovs_rwlock *rwlock, const char *where)
+    OVS_TRY_RDLOCK(0, rwlock);
+#define ovs_rwlock_tryrdlock(rwlock) \
+        ovs_rwlock_tryrdlock_at(rwlock, SOURCE_LOCATOR)
+
+/* Wrappers for xpthread_cond_*() that abort the process on any error.
+ *
+ * Use ovs_mutex_cond_wait() to wait for a condition. */
 void xpthread_cond_init(pthread_cond_t *, pthread_condattr_t *);
 void xpthread_cond_destroy(pthread_cond_t *);
 void xpthread_cond_signal(pthread_cond_t *);
 void xpthread_cond_broadcast(pthread_cond_t *);
-void xpthread_cond_wait(pthread_cond_t *, pthread_mutex_t *mutex)
-    OVS_MUST_HOLD(mutex);
 
 #ifdef __CHECKER__
 /* Replace these functions by the macros already defined in the <pthread.h>
@@ -95,8 +127,10 @@ void xpthread_cond_wait(pthread_cond_t *, pthread_mutex_t *mutex)
 #endif
 
 void xpthread_key_create(pthread_key_t *, void (*destructor)(void *));
+void xpthread_setspecific(pthread_key_t, const void *);
 
 void xpthread_create(pthread_t *, pthread_attr_t *, void *(*)(void *), void *);
+void xpthread_join(pthread_t, void **);
 \f
 /* Per-thread data.
  *
@@ -134,7 +168,15 @@ void xpthread_create(pthread_t *, pthread_attr_t *, void *(*)(void *), void *);
  * cross-thread access?     yes                no                yes
  */
 
-/* DEFINE_PER_THREAD_DATA(TYPE, NAME, INITIALIZER).
+/* For static data, use this macro in a source file:
+ *
+ *    DEFINE_STATIC_PER_THREAD_DATA(TYPE, NAME, INITIALIZER).
+ *
+ * For global data, "declare" the data in the header and "define" it in
+ * the source file, with:
+ *
+ *    DECLARE_EXTERN_PER_THREAD_DATA(TYPE, NAME).
+ *    DEFINE_EXTERN_PER_THREAD_DATA(NAME, INITIALIZER).
  *
  * One should prefer to use POSIX per-thread data, via pthread_key_t, when its
  * performance is acceptable, because of its portability (see the table above).
@@ -172,23 +214,40 @@ void xpthread_create(pthread_t *, pthread_attr_t *, void *(*)(void *), void *);
 #error
 #endif
 
-#define DEFINE_PER_THREAD_DATA(TYPE, NAME, ...)                 \
-    typedef TYPE NAME##_type;                                   \
-    static thread_local NAME##_type NAME##_var = __VA_ARGS__;   \
-                                                                \
-    static NAME##_type *                                        \
-    NAME##_get_unsafe(void)                                     \
-    {                                                           \
-        return &NAME##_var;                                     \
-    }                                                           \
-                                                                \
-    static NAME##_type *                                        \
-    NAME##_get(void)                                            \
-    {                                                           \
-        return NAME##_get_unsafe();                             \
+#define DEFINE_STATIC_PER_THREAD_DATA(TYPE, NAME, ...)                  \
+    typedef TYPE NAME##_type;                                           \
+                                                                        \
+    static NAME##_type *                                                \
+    NAME##_get_unsafe(void)                                             \
+    {                                                                   \
+        static thread_local NAME##_type var = __VA_ARGS__;              \
+        return &var;                                                    \
+    }                                                                   \
+                                                                        \
+    static NAME##_type *                                                \
+    NAME##_get(void)                                                    \
+    {                                                                   \
+        return NAME##_get_unsafe();                                     \
     }
+#define DECLARE_EXTERN_PER_THREAD_DATA(TYPE, NAME)                      \
+    typedef TYPE NAME##_type;                                           \
+    extern thread_local NAME##_type NAME##_var;                         \
+                                                                        \
+    static inline NAME##_type *                                         \
+    NAME##_get_unsafe(void)                                             \
+    {                                                                   \
+        return &NAME##_var;                                             \
+    }                                                                   \
+                                                                        \
+    static inline NAME##_type *                                         \
+    NAME##_get(void)                                                    \
+    {                                                                   \
+        return NAME##_get_unsafe();                                     \
+    }
+#define DEFINE_EXTERN_PER_THREAD_DATA(NAME, ...)         \
+    thread_local NAME##_type NAME##_var = __VA_ARGS__;
 #else  /* no C implementation support for thread-local storage  */
-#define DEFINE_PER_THREAD_DATA(TYPE, NAME, ...)                         \
+#define DEFINE_STATIC_PER_THREAD_DATA(TYPE, NAME, ...)                  \
     typedef TYPE NAME##_type;                                           \
     static pthread_key_t NAME##_key;                                    \
                                                                         \
@@ -219,7 +278,44 @@ void xpthread_create(pthread_t *, pthread_attr_t *, void *(*)(void *), void *);
                                                                         \
             value = xmalloc(sizeof *value);                             \
             *value = initial_value;                                     \
-            pthread_setspecific(NAME##_key, value);                     \
+            xpthread_setspecific(NAME##_key, value);                    \
+        }                                                               \
+        return value;                                                   \
+    }
+#define DECLARE_EXTERN_PER_THREAD_DATA(TYPE, NAME)                      \
+    typedef TYPE NAME##_type;                                           \
+    static pthread_key_t NAME##_key;                                    \
+                                                                        \
+    static inline NAME##_type *                                         \
+    NAME##_get_unsafe(void)                                             \
+    {                                                                   \
+        return pthread_getspecific(NAME##_key);                         \
+    }                                                                   \
+                                                                        \
+    NAME##_type *NAME##_get(void);
+#define DEFINE_EXTERN_PER_THREAD_DATA(NAME, ...)                        \
+    static void                                                         \
+    NAME##_once_init(void)                                              \
+    {                                                                   \
+        if (pthread_key_create(&NAME##_key, free)) {                    \
+            abort();                                                    \
+        }                                                               \
+    }                                                                   \
+                                                                        \
+    NAME##_type *                                                       \
+    NAME##_get(void)                                                    \
+    {                                                                   \
+        static pthread_once_t once = PTHREAD_ONCE_INIT;                 \
+        NAME##_type *value;                                             \
+                                                                        \
+        pthread_once(&once, NAME##_once_init);                          \
+        value = NAME##_get_unsafe();                                    \
+        if (!value) {                                                   \
+            static const NAME##_type initial_value = __VA_ARGS__;       \
+                                                                        \
+            value = xmalloc(sizeof *value);                             \
+            *value = initial_value;                                     \
+            xpthread_setspecific(NAME##_key, value);                    \
         }                                                               \
         return value;                                                   \
     }
@@ -290,7 +386,7 @@ void xpthread_create(pthread_t *, pthread_attr_t *, void *(*)(void *), void *);
     NAME##_set_unsafe(TYPE value)                       \
     {                                                   \
         TYPE old_value = NAME##_get_unsafe();           \
-        pthread_setspecific(NAME##_key, value);         \
+        xpthread_setspecific(NAME##_key, value);        \
         return old_value;                               \
     }                                                   \
                                                         \
@@ -335,22 +431,25 @@ void xpthread_create(pthread_t *, pthread_attr_t *, void *(*)(void *), void *);
 
 struct ovsthread_once {
     atomic_bool done;
-    pthread_mutex_t mutex;
+    struct ovs_mutex mutex;
 };
 
 #define OVSTHREAD_ONCE_INITIALIZER              \
     {                                           \
         ATOMIC_VAR_INIT(false),                 \
-        PTHREAD_ADAPTIVE_MUTEX_INITIALIZER,     \
+        OVS_MUTEX_INITIALIZER,                  \
     }
 
-static inline bool ovsthread_once_start(struct ovsthread_once *);
-void ovsthread_once_done(struct ovsthread_once *once) OVS_RELEASES(once);
+static inline bool ovsthread_once_start(struct ovsthread_once *once)
+    OVS_TRY_LOCK(true, once->mutex);
+void ovsthread_once_done(struct ovsthread_once *once)
+    OVS_RELEASES(once->mutex);
 
-bool ovsthread_once_start__(struct ovsthread_once *);
+bool ovsthread_once_start__(struct ovsthread_once *once)
+    OVS_TRY_LOCK(false, once->mutex);
 
 static inline bool
-ovsthread_once_is_done__(const struct ovsthread_once *once)
+ovsthread_once_is_done__(struct ovsthread_once *once)
 {
     bool done;
 
@@ -371,11 +470,23 @@ ovsthread_once_start(struct ovsthread_once *once)
     return OVS_UNLIKELY(!ovsthread_once_is_done__(once)
                         && !ovsthread_once_start__(once));
 }
+\f
+/* Thread ID.
+ *
+ * pthread_t isn't so nice for some purposes.  Its size and representation are
+ * implementation dependent, which means that there is no way to hash it.
+ * This thread ID avoids the problem.
+ */
 
-#ifdef __CHECKER__
-#define ovsthread_once_start(ONCE) \
-    ((ONCE)->done ? false : ({ OVS_ACQUIRE(ONCE); true; }))
-#endif
+DECLARE_EXTERN_PER_THREAD_DATA(unsigned int, ovsthread_id);
+
+/* Returns a per-thread identifier unique within the lifetime of the
+ * process. */
+static inline unsigned int
+ovsthread_id_self(void)
+{
+    return *ovsthread_id_get();
+}
 \f
 void assert_single_threaded_at(const char *where);
 #define assert_single_threaded() assert_single_threaded_at(SOURCE_LOCATOR)