diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/asterisk/lock.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/include/asterisk/lock.h b/include/asterisk/lock.h index 92299f3cd..475e49a99 100644 --- a/include/asterisk/lock.h +++ b/include/asterisk/lock.h @@ -289,6 +289,18 @@ int ast_find_lock_info(void *lock_addr, char *filename, size_t filename_size, in } \ } 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) \ do { \ 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)); \ 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) \ if (__res < 0) { /* Shouldn't ever happen, but just in case... */ \ ast_mutex_lock(lock); \ |