Merged revisions 118955,118957 via svnmerge from

https://origsvn.digium.com/svn/asterisk/trunk

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r118955 | tilghman | 2008-05-29 12:35:19 -0500 (Thu, 29 May 2008) | 11 lines

Merged revisions 118953 via svnmerge from 
https://origsvn.digium.com/svn/asterisk/branches/1.4

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r118953 | tilghman | 2008-05-29 12:20:16 -0500 (Thu, 29 May 2008) | 3 lines

Add some debugging code that ensures that when we do deadlock avoidance, we
don't lose the information about how a lock was originally acquired.

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r118957 | tilghman | 2008-05-29 12:39:50 -0500 (Thu, 29 May 2008) | 10 lines

Merged revisions 118954 via svnmerge from 
https://origsvn.digium.com/svn/asterisk/branches/1.4

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r118954 | tilghman | 2008-05-29 12:33:01 -0500 (Thu, 29 May 2008) | 2 lines

Define also when not DEBUG_THREADS

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git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.6.0@118958 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 37 insertions, 0 deletions

diff --git a/include/asterisk/lock.h b/include/asterisk/lock.h
index edc285a5f..e7dfb3075 100644
--- a/include/asterisk/lock.h
+++ b/include/asterisk/lock.h
@@ -186,6 +186,38 @@ void ast_remove_lock_info(void *lock_addr);
 #define ast_remove_lock_info(ignore)
 #endif
 
+/*!
+ * \brief retrieve lock info for the specified mutex
+ *
+ * this gets called during deadlock avoidance, so that the information may
+ * be preserved as to what location originally acquired the lock.
+ */
+#if !defined(LOW_MEMORY)
+int ast_find_lock_info(void *lock_addr, const char **filename, int *lineno, const char **func, const char **mutex_name);
+#else
+#define ast_find_lock_info(a,b,c,d,e) -1
+#endif
+
+/*!
+ * \brief Unlock a lock briefly
+ *
+ * used during deadlock avoidance, to preserve the original location where
+ * a lock was originally acquired.
+ */
+#define DEADLOCK_AVOIDANCE(lock) \
+	do { \
+		const char *__filename, *__func, *__mutex_name; \
+		int __lineno; \
+		int __res = ast_find_lock_info(lock, &__filename, &__lineno, &__func, &__mutex_name); \
+		ast_mutex_unlock(lock); \
+		usleep(1); \
+		if (__res < 0) { /* Shouldn't ever happen, but just in case... */ \
+			ast_mutex_lock(lock); \
+		} else { \
+			__ast_pthread_mutex_lock(__filename, __lineno, __func, __mutex_name, lock); \
+		} \
+	} while (0)
+
 static void __attribute__((constructor)) init_empty_mutex(void)
 {
 	memset(&empty_mutex, 0, sizeof(empty_mutex));
@@ -1035,6 +1067,11 @@ static inline int _ast_rwlock_trywrlock(ast_rwlock_t *lock, const char *name,
 
 #else /* !DEBUG_THREADS */
 
+#define	DEADLOCK_AVOIDANCE(lock) \
+	ast_mutex_lock(lock); \
+	usleep(1); \
+	ast_mutex_unlock(lock);
+
 static inline int ast_rwlock_init(ast_rwlock_t *prwlock)
 {
 	int res;