New functions for locking a channel - these simplify debugging
authorOlle Johansson <oej@edvina.net>
Sat, 15 Apr 2006 08:07:50 +0000 (08:07 +0000)
committerOlle Johansson <oej@edvina.net>
Sat, 15 Apr 2006 08:07:50 +0000 (08:07 +0000)
when you have channel locking issues.
(Part of the SIP transfer patch, where I had a *lot* of
channel locking problems)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@20264 65c4cc65-6c06-0410-ace0-fbb531ad65f3

Makefile
channel.c
channels/chan_sip.c
include/asterisk/lock.h

index a285413..ff9d077 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -90,6 +90,10 @@ WITH_SMDI = 1
 # Optional debugging parameters
 DEBUG_THREADS = #-DDUMP_SCHEDULER #-DDEBUG_SCHEDULER #-DDEBUG_THREADS #-DDO_CRASH #-DDETECT_DEADLOCKS
 
+# If you want to debug channel locking, try this (depends on code using
+# ast_channel_lock and companions to work)
+DEBUG_THREADS += #-DDEBUG_CHANNEL_LOCKS
+
 # Uncomment next one to enable ast_frame tracing (for debugging)
 TRACE_FRAMES = #-DTRACE_FRAMES
 
index f813e32..303cc32 100644 (file)
--- a/channel.c
+++ b/channel.c
@@ -4187,3 +4187,127 @@ const char *channelreloadreason2txt(enum channelreloadreason reason)
                return "MANAGERRELOAD (Channel module reload by manager)";
        }
 };
+
+#ifdef DEBUG_CHANNEL_LOCKS
+
+/*! \brief Unlock AST channel (and print debugging output) 
+\note You need to enable DEBUG_CHANNEL_LOCKS for this function
+*/
+int ast_channel_unlock(struct ast_channel *chan)
+{
+       int res = 0;
+       if (option_debug > 2) 
+               ast_log(LOG_DEBUG, "::::==== Unlocking AST channel %s\n", chan->name);
+       
+       if (!chan) {
+               ast_log(LOG_DEBUG, "::::==== Unlocking non-existing channel \n");
+               return 0;
+       }
+
+       res = ast_mutex_unlock(&chan->lock);
+
+       if (option_debug > 2) {
+               /* Try to find counter if possible on your platform 
+                       I've only found out how to do this on Linux
+                       DEBUG_THREADS changes the lock structure
+               */
+#ifdef __linux__
+               int count = 0;
+#ifdef DEBUG_THREADS
+               if ((count = chan->lock.mutex.__m_count))
+#else
+               if ((count = chan->lock.__m_count))
+#endif
+                       ast_log(LOG_DEBUG, ":::=== Still have %d locks (recursive)\n", count);
+#endif
+               if (!res)
+                       ast_log(LOG_DEBUG, "::::==== Channel %s was unlocked\n", chan->name);
+                       if (res == EINVAL) {
+                               ast_log(LOG_DEBUG, "::::==== Channel %s had no lock by this thread. Failed unlocking\n", chan->name);
+                       }
+               }
+               if (res == EPERM) {
+                       /* We had no lock, so okay any way*/
+                       if (option_debug > 3)
+                               ast_log(LOG_DEBUG, "::::==== Channel %s was not locked at all \n", chan->name);
+               res = 0;
+       }
+       return res;
+}
+
+/*! \brief Lock AST channel (and print debugging output)
+\note You need to enable DEBUG_CHANNEL_LOCKS for this function */
+int ast_channel_lock(struct ast_channel *chan)
+{
+       int res;
+
+       if (option_debug > 3)
+               ast_log(LOG_DEBUG, "====:::: Locking AST channel %s\n", chan->name);
+
+       res = ast_mutex_lock(&chan->lock);
+
+       if (option_debug > 3) {
+#ifdef __linux__
+               int count = 0;
+#ifdef DEBUG_THREADS
+               if ((count = chan->lock.mutex.__m_count))
+#else
+               if ((count = chan->lock.__m_count))
+#endif
+                       ast_log(LOG_DEBUG, ":::=== Now have %d locks (recursive)\n", count);
+#endif
+               if (!res)
+                       ast_log(LOG_DEBUG, "::::==== Channel %s was locked\n", chan->name);
+               if (res == EDEADLK) {
+               /* We had no lock, so okey any way */
+               if (option_debug > 3)
+                       ast_log(LOG_DEBUG, "::::==== Channel %s was not locked by us. Lock would cause deadlock.\n", chan->name);
+               }
+               if (res == EINVAL) {
+                       if (option_debug > 3)
+                               ast_log(LOG_DEBUG, "::::==== Channel %s lock failed. No mutex.\n", chan->name);
+               }
+       }
+       return res;
+}
+
+/*! \brief Lock AST channel (and print debugging output)
+\note  You need to enable DEBUG_CHANNEL_LOCKS for this function */
+int __ast_channel_trylock(struct ast_channel *chan)
+{
+       int res;
+
+       if (option_debug > 2)
+               ast_log(LOG_DEBUG, "====:::: Trying to lock AST channel %s\n", chan->name);
+
+       res = ast_mutex_trylock(&chan->lock);
+
+       if (option_debug > 2) {
+#ifdef __linux__
+               int count = 0;
+#ifdef DEBUG_THREADS
+               if ((count = chan->lock.mutex.__m_count))
+#else
+               if ((count = chan->lock.__m_count))
+#endif
+                       ast_log(LOG_DEBUG, ":::=== Now have %d locks (recursive)\n", count);
+#endif
+               if (!res)
+                       ast_log(LOG_DEBUG, "::::==== Channel %s was locked\n", chan->name);
+               if (res == EBUSY) {
+                       /* We failed to lock */
+                       if (option_debug > 2)
+                               ast_log(LOG_DEBUG, "::::==== Channel %s failed to lock. Not waiting around...\n", chan->name);
+               }
+               if (res == EDEADLK) {
+                       /* We had no lock, so okey any way*/
+                       if (option_debug > 2)
+                               ast_log(LOG_DEBUG, "::::==== Channel %s was not locked. Lock would cause deadlock.\n", chan->name);
+               }
+               if (res == EINVAL && option_debug > 2)
+                       ast_log(LOG_DEBUG, "::::==== Channel %s lock failed. No mutex.\n", chan->name);
+       }
+       return res;
+}
+
+#endif
index 2f12391..2624969 100644 (file)
@@ -1344,7 +1344,7 @@ static int retrans_pkt(void *data)
        int reschedule = DEFAULT_RETRANS;
 
        /* Lock channel */
-       ast_mutex_lock(&pkt->owner->lock);
+       ast_channel_lock(&pkt->owner);
 
        if (pkt->retrans < MAX_RETRANS) {
                pkt->retrans++;
@@ -1381,7 +1381,7 @@ static int retrans_pkt(void *data)
 
                append_history(pkt->owner, "ReTx", "%d %s", reschedule, pkt->data);
                __sip_xmit(pkt->owner, pkt->data, pkt->packetlen);
-               ast_mutex_unlock(&pkt->owner->lock);
+               ast_channel_unlock(&pkt->owner);
                return  reschedule;
        } 
        /* Too many retries */
index 97deac1..ab6dde3 100644 (file)
@@ -761,4 +761,16 @@ AST_INLINE_API(int ast_atomic_dec_and_test(volatile int *p),
 }
 )
 
+#ifndef DEBUG_CHANNEL_LOCKS
+/*! \brief Lock a channel. If DEBUG_CHANNEL_LOCKS is defined 
+       in the Makefile, print relevant output for debugging */
+#define ast_channel_lock(x)            ast_mutex_lock(x->lock);
+/*! \brief Unlock a channel. If DEBUG_CHANNEL_LOCKS is defined 
+       in the Makefile, print relevant output for debugging */
+#define ast_channel_unlock(x)          ast_mutex_unlock(x->lock);
+/*! \brief Try locking a channel. If DEBUG_CHANNEL_LOCKS is defined 
+       in the Makefile, print relevant output for debugging */
+#define ast_channel_trylock(x)         ast_mutex_trylock(x->lock);
+#endif
+
 #endif /* _ASTERISK_LOCK_H */