More expansion of the deadlock avoidance macro, including a macro to do locking

of the channel lock

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@125020 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_dahdi.c b/channels/chan_dahdi.c
index 54d8b43..0050d6c 100644 (file)
--- a/channels/chan_dahdi.c
+++ b/channels/chan_dahdi.c
@@ -898,10 +898,7 @@ static inline int ss7_grab(struct dahdi_pvt *pvt, struct dahdi_ss7 *pri)
        do {
                res = ast_mutex_trylock(&pri->lock);
                if (res) {
-                       ast_mutex_unlock(&pvt->lock);
-                       /* Release the lock and try again */
-                       usleep(1);
-                       ast_mutex_lock(&pvt->lock);
+                       DEADLOCK_AVOIDANCE(&pvt->lock);
                }
        } while (res);
        /* Then break the poll */
@@ -3755,9 +3752,7 @@ static enum ast_bridge_result dahdi_bridge(struct ast_channel *c0, struct ast_ch
 
        ast_channel_lock(c0);
        while (ast_channel_trylock(c1)) {
-               ast_channel_unlock(c0);
-               usleep(1);
-               ast_channel_lock(c0);
+               CHANNEL_DEADLOCK_AVOIDANCE(c0);
        }
 
        p0 = c0->tech_pvt;
@@ -3927,9 +3922,7 @@ static enum ast_bridge_result dahdi_bridge(struct ast_channel *c0, struct ast_ch
                
                ast_channel_lock(c0);
                while (ast_channel_trylock(c1)) {
-                       ast_channel_unlock(c0);
-                       usleep(1);
-                       ast_channel_lock(c0);
+                       CHANNEL_DEADLOCK_AVOIDANCE(c0);
                }
 
                p0 = c0->tech_pvt;
@@ -4469,14 +4462,12 @@ static struct ast_frame *dahdi_handle_event(struct ast_channel *ast)
                                                   the private structure -- not especially easy or clean */
                                                while (p->subs[SUB_THREEWAY].owner && ast_channel_trylock(p->subs[SUB_THREEWAY].owner)) {
                                                        /* Yuck, didn't get the lock on the 3-way, gotta release everything and re-grab! */
-                                                       ast_mutex_unlock(&p->lock);
-                                                       ast_channel_unlock(ast);
-                                                       usleep(1);
+                                                       DLA_UNLOCK(&p->lock);
+                                                       CHANNEL_DEADLOCK_AVOIDANCE(ast);
                                                        /* We can grab ast and p in that order, without worry.  We should make sure
                                                           nothing seriously bad has happened though like some sort of bizarre double
                                                           masquerade! */
-                                                       ast_channel_lock(ast);
-                                                       ast_mutex_lock(&p->lock);
+                                                       DLA_LOCK(&p->lock);
                                                        if (p->owner != ast) {
                                                                ast_log(LOG_WARNING, "This isn't good...\n");
                                                                return NULL;

diff --git a/channels/chan_features.c b/channels/chan_features.c
index 65146f4..74e2d16 100644 (file)
--- a/channels/chan_features.c
+++ b/channels/chan_features.c
@@ -139,9 +139,7 @@ static void wakeup_sub(struct feature_pvt *p, int a)
        for (;;) {
                if (p->subs[a].owner) {
                        if (ast_mutex_trylock(&p->subs[a].owner->lock)) {
-                               ast_mutex_unlock(&p->lock);
-                               usleep(1);
-                               ast_mutex_lock(&p->lock);
+                               DEADLOCK_AVOIDANCE(&p->lock);
                        } else {
                                ast_queue_frame(p->subs[a].owner, &null);
                                ast_mutex_unlock(&p->subs[a].owner->lock);

diff --git a/channels/chan_h323.c b/channels/chan_h323.c
index 9951d12..fc0c7f3 100644 (file)
--- a/channels/chan_h323.c
+++ b/channels/chan_h323.c
@@ -304,9 +304,7 @@ static int oh323_simulate_dtmf_end(const void *data)
                ast_mutex_lock(&pvt->lock);
                /* Don't hold pvt lock while trying to lock the channel */
                while(pvt->owner && ast_channel_trylock(pvt->owner)) {
-                       ast_mutex_unlock(&pvt->lock);
-                       usleep(1);
-                       ast_mutex_lock(&pvt->lock);
+                       DEADLOCK_AVOIDANCE(&pvt->lock);
                }
 
                if (pvt->owner) {

diff --git a/channels/chan_iax2.c b/channels/chan_iax2.c
index aeae13b..2432a6b 100644 (file)
--- a/channels/chan_iax2.c
+++ b/channels/chan_iax2.c
@@ -2248,9 +2248,7 @@ retry:
        if (owner) {
                if (ast_channel_trylock(owner)) {
                        ast_debug(3, "Avoiding IAX destroy deadlock\n");
-                       ast_mutex_unlock(&iaxsl[callno]);
-                       usleep(1);
-                       ast_mutex_lock(&iaxsl[callno]);
+                       DEADLOCK_AVOIDANCE(&iaxsl[callno]);
                        goto retry;
                }
        }

diff --git a/channels/chan_local.c b/channels/chan_local.c
index aade7b2..0a1a169 100644 (file)
--- a/channels/chan_local.c
+++ b/channels/chan_local.c
@@ -219,15 +219,13 @@ static int local_queue_frame(struct local_pvt *p, int isoutbound, struct ast_fra
 
        /* Ensure that we have both channels locked */
        while (other && ast_channel_trylock(other)) {
-               ast_mutex_unlock(&p->lock);
-               if (us && us_locked) {
-                       ast_channel_unlock(us);
-               }
-               usleep(1);
+               DLA_UNLOCK(&p->lock);
                if (us && us_locked) {
-                       ast_channel_lock(us);
+                       CHANNEL_DEADLOCK_AVOIDANCE(us);
+               } else {
+                       usleep(1);
                }
-               ast_mutex_lock(&p->lock);
+               DLA_LOCK(&p->lock);
                other = isoutbound ? p->owner : p->chan;
        }
 

diff --git a/include/asterisk/lock.h b/include/asterisk/lock.h
index 3f261c6..4122978 100644 (file)
--- a/include/asterisk/lock.h
+++ b/include/asterisk/lock.h
@@ -289,6 +289,21 @@ int ast_find_lock_info(void *lock_addr, const char **filename, int *lineno, cons
                } \
        } while (0)
 
+#define DLA_UNLOCK(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);
+
+#define DLA_LOCK(lock) \
+               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 inline void ast_reentrancy_lock(struct ast_lock_track *lt)
 {
        pthread_mutex_lock(&lt->reentr_mutex);
@@ -1429,6 +1444,10 @@ static inline int _ast_rwlock_trywrlock(ast_rwlock_t *t, const char *name,
        usleep(1); \
        ast_mutex_unlock(lock);
 
+#define DLA_UNLOCK(lock)       ast_mutex_unlock(lock)
+
+#define DLA_LOCK(lock) ast_mutex_lock(lock)
+
 typedef pthread_mutex_t ast_mutex_t;
 
 #define AST_MUTEX_INIT_VALUE                   ((ast_mutex_t) PTHREAD_MUTEX_INIT_VALUE)