Add private lock deadlock avoidance callback to PRI and SS7.

Factor out the equivalent function for analog.


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@313100 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_dahdi.c

@@ -3320,6 +3320,7 @@ static struct sig_pri_callback dahdi_pri_callbacks =
 	.dsp_reset_and_flush_digits = my_dsp_reset_and_flush_digits,
 	.lock_private = my_lock_private,
 	.unlock_private = my_unlock_private,
+	.deadlock_avoidance_private = my_deadlock_avoidance_private,
 	.new_ast_channel = my_new_pri_ast_channel,
 	.fixup_chans = my_pri_fixup_chans,
 	.set_alarm = my_set_alarm,
@@ -3483,6 +3484,7 @@ static struct sig_ss7_callback dahdi_ss7_callbacks =
 {
 	.lock_private = my_lock_private,
 	.unlock_private = my_unlock_private,
+	.deadlock_avoidance_private = my_deadlock_avoidance_private,
 
 	.set_echocanceller = my_set_echocanceller,
 	.set_loopback = my_ss7_set_loopback,

channels/sig_analog.c

@@ -518,23 +518,31 @@ static void analog_all_subchannels_hungup(struct analog_pvt *p)
 	}
 }
 
-#if 0
 static void analog_unlock_private(struct analog_pvt *p)
 {
 	if (p->calls->unlock_private) {
 		p->calls->unlock_private(p->chan_pvt);
 	}
 }
-#endif
 
-#if 0
 static void analog_lock_private(struct analog_pvt *p)
 {
 	if (p->calls->lock_private) {
 		p->calls->lock_private(p->chan_pvt);
 	}
 }
-#endif
+
+static void analog_deadlock_avoidance_private(struct analog_pvt *p)
+{
+	if (p->calls->deadlock_avoidance_private) {
+		p->calls->deadlock_avoidance_private(p->chan_pvt);
+	} else {
+		/* Fallback to manual avoidance if callback not present. */
+		analog_unlock_private(p);
+		usleep(1);
+		analog_lock_private(p);
+	}
+}
 
 /*!
  * \internal
@@ -563,12 +571,7 @@ static void analog_lock_sub_owner(struct analog_pvt *pvt, enum analog_sub sub_id
 			break;
 		}
 		/* We must unlock the private to avoid the possibility of a deadlock */
-		if (pvt->calls->deadlock_avoidance_private) {
-			pvt->calls->deadlock_avoidance_private(pvt->chan_pvt);
-		} else {
-			/* Don't use 100% CPU if required callback not present. */
-			usleep(1);
-		}
+		analog_deadlock_avoidance_private(pvt);
 	}
 }
 

channels/sig_pri.c

@@ -321,6 +321,16 @@ static void sig_pri_lock_private(struct sig_pri_chan *p)
 		p->calls->lock_private(p->chan_pvt);
 }
 
+static void sig_pri_deadlock_avoidance_private(struct sig_pri_chan *p)
+{
+	if (p->calls->deadlock_avoidance_private) {
+		p->calls->deadlock_avoidance_private(p->chan_pvt);
+	} else {
+		/* Fallback to the old way if callback not present. */
+		PRI_DEADLOCK_AVOIDANCE(p);
+	}
+}
+
 static inline int pri_grab(struct sig_pri_chan *p, struct sig_pri_span *pri)
 {
 	int res;
@@ -328,7 +338,7 @@ static inline int pri_grab(struct sig_pri_chan *p, struct sig_pri_span *pri)
 	do {
 		res = ast_mutex_trylock(&pri->lock);
 		if (res) {
-			PRI_DEADLOCK_AVOIDANCE(p);
+			sig_pri_deadlock_avoidance_private(p);
 		}
 	} while (res);
 	/* Then break the poll */
@@ -1123,7 +1133,7 @@ static void sig_pri_lock_owner(struct sig_pri_span *pri, int chanpos)
 		}
 		/* We must unlock the PRI to avoid the possibility of a deadlock */
 		ast_mutex_unlock(&pri->lock);
-		PRI_DEADLOCK_AVOIDANCE(pri->pvts[chanpos]);
+		sig_pri_deadlock_avoidance_private(pri->pvts[chanpos]);
 		ast_mutex_lock(&pri->lock);
 	}
 }

channels/sig_pri.h

@@ -167,6 +167,8 @@ struct sig_pri_callback {
 	void (* const unlock_private)(void *pvt);
 	/* Lock the private in the signalling private structure.  ... */
 	void (* const lock_private)(void *pvt);
+	/* Do deadlock avoidance for the private signaling structure lock.  */
+	void (* const deadlock_avoidance_private)(void *pvt);
 	/* Function which is called back to handle any other DTMF events that are received.  Called by analog_handle_event.  Why is this
 	 * important to use, instead of just directly using events received before they are passed into the library?  Because sometimes,
 	 * (CWCID) the library absorbs DTMF events received. */

channels/sig_ss7.c

@@ -64,6 +64,16 @@ static void sig_ss7_lock_private(struct sig_ss7_chan *p)
 	}
 }
 
+static void sig_ss7_deadlock_avoidance_private(struct sig_ss7_chan *p)
+{
+	if (p->calls->deadlock_avoidance_private) {
+		p->calls->deadlock_avoidance_private(p->chan_pvt);
+	} else {
+		/* Fallback to the old way if callback not present. */
+		SIG_SS7_DEADLOCK_AVOIDANCE(p);
+	}
+}
+
 void sig_ss7_set_alarm(struct sig_ss7_chan *p, int in_alarm)
 {
 	p->inalarm = in_alarm;
@@ -255,7 +265,7 @@ static void sig_ss7_lock_owner(struct sig_ss7_linkset *ss7, int chanpos)
 		}
 		/* We must unlock the SS7 to avoid the possibility of a deadlock */
 		ast_mutex_unlock(&ss7->lock);
-		SIG_SS7_DEADLOCK_AVOIDANCE(ss7->pvts[chanpos]);
+		sig_ss7_deadlock_avoidance_private(ss7->pvts[chanpos]);
 		ast_mutex_lock(&ss7->lock);
 	}
 }
@@ -1109,7 +1119,7 @@ static inline int ss7_grab(struct sig_ss7_chan *pvt, struct sig_ss7_linkset *ss7
 	do {
 		res = ast_mutex_trylock(&ss7->lock);
 		if (res) {
-			SIG_SS7_DEADLOCK_AVOIDANCE(pvt);
+			sig_ss7_deadlock_avoidance_private(pvt);
 		}
 	} while (res);
 	/* Then break the poll */

channels/sig_ss7.h

@@ -105,6 +105,8 @@ struct sig_ss7_callback {
 	void (* const unlock_private)(void *pvt);
 	/* Lock the private in the signaling private structure. */
 	void (* const lock_private)(void *pvt);
+	/* Do deadlock avoidance for the private signaling structure lock.  */
+	void (* const deadlock_avoidance_private)(void *pvt);
 
 	int (* const set_echocanceller)(void *pvt, int enable);
 	void (* const set_loopback)(void *pvt, int enable);