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Document DLA_UNLOCK and DLA_LOCK

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git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@125895 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Tilghman Lesher
2008-06-27 17:02:56 +00:00
parent fcfe9beca3
commit cab9430106
1 changed files with 24 additions and 0 deletions
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include/asterisk/lock.h
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@@ -289,6 +289,18 @@ int ast_find_lock_info(void *lock_addr, char *filename, size_t filename_size, in
} \ } \
} while (0) } while (0)
/*!
* \brief Deadlock avoidance unlock
*
* In certain deadlock avoidance scenarios, there is more than one lock to be
* unlocked and relocked. Therefore, this pair of macros is provided for that
* purpose. Note that every DLA_UNLOCK _MUST_ be paired with a matching
* DLA_LOCK. The intent of this pair of macros is to be used around another
* set of deadlock avoidance code, mainly CHANNEL_DEADLOCK_AVOIDANCE, as the
* locking order specifies that we may safely lock a channel, followed by its
* pvt, with no worries about a deadlock. In any other scenario, this macro
* may not be safe to use.
*/
#define DLA_UNLOCK(lock) \ #define DLA_UNLOCK(lock) \
do { \ do { \
char __filename[80], __func[80], __mutex_name[80]; \ char __filename[80], __func[80], __mutex_name[80]; \
@@ -296,6 +308,18 @@ int ast_find_lock_info(void *lock_addr, char *filename, size_t filename_size, in
int __res = ast_find_lock_info(lock, __filename, sizeof(__filename), &__lineno, __func, sizeof(__func), __mutex_name, sizeof(__mutex_name)); \ int __res = ast_find_lock_info(lock, __filename, sizeof(__filename), &__lineno, __func, sizeof(__func), __mutex_name, sizeof(__mutex_name)); \
ast_mutex_unlock(lock); ast_mutex_unlock(lock);
/*!
* \brief Deadlock avoidance lock
*
* In certain deadlock avoidance scenarios, there is more than one lock to be
* unlocked and relocked. Therefore, this pair of macros is provided for that
* purpose. Note that every DLA_UNLOCK _MUST_ be paired with a matching
* DLA_LOCK. The intent of this pair of macros is to be used around another
* set of deadlock avoidance code, mainly CHANNEL_DEADLOCK_AVOIDANCE, as the
* locking order specifies that we may safely lock a channel, followed by its
* pvt, with no worries about a deadlock. In any other scenario, this macro
* may not be safe to use.
*/
#define DLA_LOCK(lock) \ #define DLA_LOCK(lock) \
if (__res < 0) { /* Shouldn't ever happen, but just in case... */ \ if (__res < 0) { /* Shouldn't ever happen, but just in case... */ \
ast_mutex_lock(lock); \ ast_mutex_lock(lock); \