[svn-commits] dvossel: branch dvossel/masq_locking_order_trunk r221392 - in /team/dvossel/m...

SVN commits to the Digium repositories svn-commits at lists.digium.com
Wed Sep 30 15:23:19 CDT 2009


Author: dvossel
Date: Wed Sep 30 15:23:14 2009
New Revision: 221392

URL: http://svnview.digium.com/svn/asterisk?view=rev&rev=221392
Log:
This commit is my initial try at eliminating all channel locks
before a masquerade is issued.


Modified:
    team/dvossel/masq_locking_order_trunk/channels/chan_sip.c
    team/dvossel/masq_locking_order_trunk/main/channel.c
    team/dvossel/masq_locking_order_trunk/main/features.c
    team/dvossel/masq_locking_order_trunk/main/pbx.c

Modified: team/dvossel/masq_locking_order_trunk/channels/chan_sip.c
URL: http://svnview.digium.com/svn/asterisk/team/dvossel/masq_locking_order_trunk/channels/chan_sip.c?view=diff&rev=221392&r1=221391&r2=221392
==============================================================================
--- team/dvossel/masq_locking_order_trunk/channels/chan_sip.c (original)
+++ team/dvossel/masq_locking_order_trunk/channels/chan_sip.c Wed Sep 30 15:23:14 2009
@@ -19181,17 +19181,14 @@
 	}
 	ast_debug(4, "SIP Park: Transferer channel %s, Transferee %s\n", transferer->name, transferee->name);
 
-	ast_channel_lock(transferee);
 	if (ast_do_masquerade(transferee)) {
 		ast_log(LOG_WARNING, "Masquerade failed.\n");
 		transmit_response(transferer->tech_pvt, "503 Internal error", &req);
-		ast_channel_unlock(transferee);
 		if (d->req.data)
 			ast_free(d->req.data);
 		free(d);
 		return NULL;
 	}
-	ast_channel_unlock(transferee);
 
 	res = ast_park_call(transferee, transferer, 0, &ext);
 	
@@ -19290,15 +19287,12 @@
 	ast_copy_string(transferer->exten, chan2->exten, sizeof(transferer->exten));
 	transferer->priority = chan2->priority;
 
-	ast_channel_lock(transferer);
 	if (ast_do_masquerade(transferer)) {
 		ast_log(LOG_WARNING, "Masquerade failed :(\n");
-		ast_channel_unlock(transferer);
 		transferer->hangupcause = AST_CAUSE_SWITCH_CONGESTION;
 		ast_hangup(transferer);
 		return -1;
 	}
-	ast_channel_unlock(transferer);
 	if (!transferer || !transferee) {
 		if (!transferer) {
 			ast_debug(1, "No transferer channel, giving up parking\n");
@@ -19734,10 +19728,13 @@
 	else
 		ast_debug(4, "Invite/Replaces: Going to masquerade %s into %s\n", c->name, replacecall->name);
 
-	/* C should now be in place of replacecall */
+	/* C should now be in place of replacecall. all channel locks should be removed before issuing the masq */
+	ast_channel_unlock(replacecall);
+	ast_channel_unlock(c);
 	if (ast_do_masquerade(replacecall)) {
 		ast_log(LOG_WARNING, "Failed to perform masquerade with INVITE replaces\n");
 	}
+	ast_channel_lock_both(replacecall, c);
 
 	if (earlyreplace || oneleggedreplace ) {
 		c->hangupcause = AST_CAUSE_SWITCH_CONGESTION;
@@ -21589,6 +21586,7 @@
 		while (bridge && ast_channel_trylock(bridge)) {
 			ast_channel_unlock(p->owner);
 			do {
+			ast_channel_unlock(p->owner);
 				/* Can't use DEADLOCK_AVOIDANCE since p is an ao2 object */
 				sip_pvt_unlock(p);
 				usleep(1);
@@ -21662,7 +21660,9 @@
 				if (bridged_to) {
 					/* Don't actually hangup here... */
 					ast_queue_control(c, AST_CONTROL_UNHOLD);
+					ast_channel_unlock(c);  /* async_goto can do a masquerade, no locks can be held during a masq */
 					ast_async_goto(bridged_to, p->context, p->refer->refer_to, 1);
+					ast_channel_lock(c);
 				} else
 					ast_queue_hangup(p->owner);
 			}

Modified: team/dvossel/masq_locking_order_trunk/main/channel.c
URL: http://svnview.digium.com/svn/asterisk/team/dvossel/masq_locking_order_trunk/main/channel.c?view=diff&rev=221392&r1=221391&r2=221392
==============================================================================
--- team/dvossel/masq_locking_order_trunk/main/channel.c (original)
+++ team/dvossel/masq_locking_order_trunk/main/channel.c Wed Sep 30 15:23:14 2009
@@ -2143,8 +2143,11 @@
 	ast_autoservice_stop(chan);
 
 	if (chan->masq) {
-		if (ast_do_masquerade(chan))
+		ast_channel_unlock(chan);
+		if (ast_do_masquerade(chan)) {
 			ast_log(LOG_WARNING, "Failed to perform masquerade\n");
+		}
+		ast_channel_lock(chan);
 	}
 
 	if (chan->masq) {
@@ -2514,13 +2517,13 @@
 	
 	/* Perform any pending masquerades */
 	for (x = 0; x < n; x++) {
-		ast_channel_lock(c[x]);
 		if (c[x]->masq && ast_do_masquerade(c[x])) {
 			ast_log(LOG_WARNING, "Masquerade failed\n");
 			*ms = -1;
-			ast_channel_unlock(c[x]);
 			return NULL;
 		}
+
+		ast_channel_lock(c[x]);
 		if (!ast_tvzero(c[x]->whentohangup)) {
 			if (ast_tvzero(whentohangup))
 				now = ast_tvnow();
@@ -2641,16 +2644,15 @@
 	struct ast_channel *winner = NULL;
 	struct ast_epoll_data *aed = NULL;
 
-	ast_channel_lock(chan);
 
 	/* See if this channel needs to be masqueraded */
 	if (chan->masq && ast_do_masquerade(chan)) {
 		ast_log(LOG_WARNING, "Failed to perform masquerade on %s\n", chan->name);
 		*ms = -1;
-		ast_channel_unlock(chan);
 		return NULL;
 	}
 
+	ast_channel_lock(chan);
 	/* Figure out their timeout */
 	if (!ast_tvzero(chan->whentohangup)) {
 		if ((diff = ast_tvdiff_ms(chan->whentohangup, ast_tvnow())) < 0) {
@@ -2726,13 +2728,13 @@
 	struct ast_channel *winner = NULL;
 
 	for (i = 0; i < n; i++) {
-		ast_channel_lock(c[i]);
 		if (c[i]->masq && ast_do_masquerade(c[i])) {
 			ast_log(LOG_WARNING, "Masquerade failed\n");
 			*ms = -1;
-			ast_channel_unlock(c[i]);
 			return NULL;
 		}
+
+		ast_channel_lock(c[i]);
 		if (!ast_tvzero(c[i]->whentohangup)) {
 			if (whentohangup == 0)
 				now = ast_tvnow();
@@ -3067,21 +3069,22 @@
 	int count = 0, cause = 0;
 
 	/* this function is very long so make sure there is only one return
-	 * point at the end (there are only two exceptions to this).
+	 * point at the end (there are only three exceptions to this).
 	 */
+
+	if (chan->masq) {
+		if (ast_do_masquerade(chan))
+			ast_log(LOG_WARNING, "Failed to perform masquerade\n");
+		else
+			f =  &ast_null_frame;
+		return f;
+	}
+
 	while(ast_channel_trylock(chan)) {
 		if(count++ > 10) 
 			/*cannot goto done since the channel is not locked*/
 			return &ast_null_frame;
 		usleep(1);
-	}
-
-	if (chan->masq) {
-		if (ast_do_masquerade(chan))
-			ast_log(LOG_WARNING, "Failed to perform masquerade\n");
-		else
-			f =  &ast_null_frame;
-		goto done;
 	}
 
 	/* Stop if we're a zombie or need a soft hangup */
@@ -3893,9 +3896,13 @@
 		goto done;
 
 	/* Handle any pending masquerades */
-	if (chan->masq && ast_do_masquerade(chan)) {
-		ast_log(LOG_WARNING, "Failed to perform masquerade\n");
-		goto done;
+	if (chan->masq) {
+		ast_channel_unlock(chan);
+		if (ast_do_masquerade(chan)) {
+			ast_log(LOG_WARNING, "Failed to perform masquerade\n");
+			return res; /* no need to goto done: chan is already unlocked for masq */
+		}
+		ast_channel_lock(chan);
 	}
 	if (chan->masqr) {
 		res = 0;	/* XXX explain, why 0 ? */
@@ -5063,7 +5070,9 @@
 /*!
   \brief Masquerade a channel
 
-  \note Assumes channel will be locked when called
+  \note Assumes _NO_ channels are locked.  If a channel is locked while calling
+        this function, it invalidates our channel container locking order.  All channels
+		must be unlocked before it is permissible to lock the channels' ao2 container.
 */
 int ast_do_masquerade(struct ast_channel *original)
 {

Modified: team/dvossel/masq_locking_order_trunk/main/features.c
URL: http://svnview.digium.com/svn/asterisk/team/dvossel/masq_locking_order_trunk/main/features.c?view=diff&rev=221392&r1=221391&r2=221392
==============================================================================
--- team/dvossel/masq_locking_order_trunk/main/features.c (original)
+++ team/dvossel/masq_locking_order_trunk/main/features.c Wed Sep 30 15:23:14 2009
@@ -4378,17 +4378,19 @@
 static void do_bridge_masquerade(struct ast_channel *chan, struct ast_channel *tmpchan)
 {
 	ast_moh_stop(chan);
-	ast_channel_lock(chan);
+	ast_channel_lock_both(chan, tmpchan);
 	ast_setstate(tmpchan, chan->_state);
 	tmpchan->readformat = chan->readformat;
 	tmpchan->writeformat = chan->writeformat;
 	ast_channel_masquerade(tmpchan, chan);
-	ast_channel_lock(tmpchan);
+	ast_channel_unlock(chan);
+	ast_channel_unlock(tmpchan);
+
+	/* must be done without any channel locks held */
 	ast_do_masquerade(tmpchan);
+
 	/* when returning from bridge, the channel will continue at the next priority */
 	ast_explicit_goto(tmpchan, chan->context, chan->exten, chan->priority + 1);
-	ast_channel_unlock(tmpchan);
-	ast_channel_unlock(chan);
 }
 
 /*!
@@ -5004,9 +5006,10 @@
 					"Channel1: %s\r\n"
 					"Channel2: %s\r\n", chan->name, args.dest_chan);
 	}
+
+	ast_channel_unlock(current_dest_chan);
+
 	do_bridge_masquerade(current_dest_chan, final_dest_chan);
-
-	ast_channel_unlock(current_dest_chan);
 
 	/* now current_dest_chan is a ZOMBIE and with softhangup set to 1 and final_dest_chan is our end point */
 	/* try to make compatible, send error if we fail */

Modified: team/dvossel/masq_locking_order_trunk/main/pbx.c
URL: http://svnview.digium.com/svn/asterisk/team/dvossel/masq_locking_order_trunk/main/pbx.c?view=diff&rev=221392&r1=221391&r2=221392
==============================================================================
--- team/dvossel/masq_locking_order_trunk/main/pbx.c (original)
+++ team/dvossel/masq_locking_order_trunk/main/pbx.c Wed Sep 30 15:23:14 2009
@@ -7662,10 +7662,12 @@
 				tmpchan = NULL;
 				res = -1;
 			} else {
-				/* Grab the locks and get going */
-				ast_channel_lock(tmpchan);
+				/* it may appear odd to unlock chan here since the masquerade is on
+				 * tmpchan, but no channel locks should be held when doing a masquerade
+				 * since a masquerade requires a lock on the channels ao2 container. */
+				ast_channel_unlock(chan);
 				ast_do_masquerade(tmpchan);
-				ast_channel_unlock(tmpchan);
+				ast_channel_lock(chan);
 				/* Start the PBX going on our stolen channel */
 				if (ast_pbx_start(tmpchan)) {
 					ast_log(LOG_WARNING, "Unable to start PBX on %s\n", tmpchan->name);




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