Remove the unsafe bridge parameter from ast_bridge_hook_callback's.

Most hook callbacks did not need the bridge parameter.  The pointer value
could become invalid if the channel is moved to another bridge while it is
executing.

* Fixed some issues in feature_attended_transfer() as a result.

* Reduce the bridge inhibit count in
attended_transfer_properties_shutdown() after it has restored the bridge
channel hooks.

* Removed basic bridge requirement on feature_blind_transfer().  It does
not require the basic bridge like feature_attended_transfer().


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@395574 65c4cc65-6c06-0410-ace0-fbb531ad65f3

14 files changed, 103 insertions, 93 deletions

diff --git a/apps/app_agent_pool.c b/apps/app_agent_pool.c
index 6ed2ccad1..6beb90a95 100644
--- a/apps/app_agent_pool.c
+++ b/apps/app_agent_pool.c
@@ -1078,12 +1078,11 @@ static void agent_connect_caller(struct ast_bridge_channel *bridge_channel, stru
 		 * The agent is in the new bridge so we can invoke the
 		 * mixmonitor hook to only start recording.
 		 */
-		ast_bridge_features_do(AST_BRIDGE_BUILTIN_AUTOMIXMON, caller_bridge,
-			bridge_channel, &options);
+		ast_bridge_features_do(AST_BRIDGE_BUILTIN_AUTOMIXMON, bridge_channel, &options);
 	}
 }
 
-static int bridge_agent_hold_ack(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int bridge_agent_hold_ack(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct agent_pvt *agent = hook_pvt;
 
@@ -1101,7 +1100,7 @@ static int bridge_agent_hold_ack(struct ast_bridge *bridge, struct ast_bridge_ch
 	return 0;
 }
 
-static int bridge_agent_hold_heartbeat(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int bridge_agent_hold_heartbeat(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct agent_pvt *agent = hook_pvt;
 	int probation_timedout = 0;
@@ -1709,7 +1708,7 @@ static void caller_abort_agent(struct agent_pvt *agent)
 	ast_bridge_channel_unlock(logged);
 }
 
-static int caller_safety_timeout(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int caller_safety_timeout(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct agent_pvt *agent = hook_pvt;
 
diff --git a/apps/app_bridgewait.c b/apps/app_bridgewait.c
index bdfd87e62..5697a79d0 100644
--- a/apps/app_bridgewait.c
+++ b/apps/app_bridgewait.c
@@ -201,7 +201,7 @@ AST_APP_OPTIONS(bridgewait_opts, {
 	AST_APP_OPTION_ARG('S', MUXFLAG_TIMEOUT, OPT_ARG_TIMEOUT),
 });
 
-static int bridgewait_timeout_callback(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int bridgewait_timeout_callback(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	ast_verb(3, "Channel %s timed out.\n", ast_channel_name(bridge_channel->chan));
 	ast_bridge_channel_leave_bridge(bridge_channel, BRIDGE_CHANNEL_STATE_END);
diff --git a/apps/app_confbridge.c b/apps/app_confbridge.c
index 3b58a4d86..01060976d 100644
--- a/apps/app_confbridge.c
+++ b/apps/app_confbridge.c
@@ -1402,9 +1402,9 @@ static void conf_handle_talker_destructor(void *pvt_data)
 	ast_free(pvt_data);
 }
 
-static int conf_handle_talker_cb(struct ast_bridge_channel *bridge_channel, void *pvt_data, int talking)
+static int conf_handle_talker_cb(struct ast_bridge_channel *bridge_channel, void *hook_pvt, int talking)
 {
-	const char *conf_name = pvt_data;
+	const char *conf_name = hook_pvt;
 	struct confbridge_conference *conference = ao2_find(conference_bridges, conf_name, OBJ_KEY);
 	struct ast_json *talking_extras;
 
diff --git a/apps/confbridge/conf_config_parser.c b/apps/confbridge/conf_config_parser.c
index 58431ca3c..984787cb2 100644
--- a/apps/confbridge/conf_config_parser.c
+++ b/apps/confbridge/conf_config_parser.c
@@ -2080,9 +2080,10 @@ static void menu_hook_destroy(void *hook_pvt)
 	ast_free(pvt);
 }
 
-static int menu_hook_callback(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int menu_hook_callback(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct dtmf_menu_hook_pvt *pvt = hook_pvt;
+
 	return conf_handle_dtmf(bridge_channel, pvt->user, &pvt->menu_entry, pvt->menu);
 }
 
diff --git a/bridges/bridge_builtin_features.c b/bridges/bridge_builtin_features.c
index 324969f33..c22b83548 100644
--- a/bridges/bridge_builtin_features.c
+++ b/bridges/bridge_builtin_features.c
@@ -214,7 +214,7 @@ static void start_automonitor(struct ast_bridge_channel *bridge_channel, struct
 	pbx_builtin_setvar_helper(peer_chan, "TOUCH_MONITOR_OUTPUT", touch_filename);
 }
 
-static int feature_automonitor(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int feature_automonitor(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	const char *start_message;
 	const char *stop_message;
@@ -226,7 +226,9 @@ static int feature_automonitor(struct ast_bridge *bridge, struct ast_bridge_chan
 	RAII_VAR(struct ast_features_general_config *, features_cfg, NULL, ao2_cleanup);
 
 	features_cfg = ast_get_chan_features_general_config(bridge_channel->chan);
-	peer_chan = ast_bridge_peer(bridge, bridge_channel->chan);
+	ast_bridge_channel_lock_bridge(bridge_channel);
+	peer_chan = ast_bridge_peer_nolock(bridge_channel->bridge, bridge_channel->chan);
+	ast_bridge_unlock(bridge_channel->bridge);
 
 	if (!peer_chan) {
 		ast_verb(3, "Cannot start AutoMonitor for %s - can not determine peer in bridge.\n",
@@ -397,7 +399,7 @@ static void start_automixmonitor(struct ast_bridge_channel *bridge_channel, stru
 	pbx_builtin_setvar_helper(peer_chan, "TOUCH_MIXMONITOR_OUTPUT", touch_filename);
 }
 
-static int feature_automixmonitor(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int feature_automixmonitor(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	static const char *mixmonitor_spy_type = "MixMonitor";
 	const char *stop_message;
@@ -410,7 +412,9 @@ static int feature_automixmonitor(struct ast_bridge *bridge, struct ast_bridge_c
 	RAII_VAR(struct ast_features_general_config *, features_cfg, NULL, ao2_cleanup);
 
 	features_cfg = ast_get_chan_features_general_config(bridge_channel->chan);
-	peer_chan = ast_bridge_peer(bridge, bridge_channel->chan);
+	ast_bridge_channel_lock_bridge(bridge_channel);
+	peer_chan = ast_bridge_peer_nolock(bridge_channel->bridge, bridge_channel->chan);
+	ast_bridge_unlock(bridge_channel->bridge);
 
 	if (!peer_chan) {
 		ast_verb(3, "Cannot do AutoMixMonitor for %s - cannot determine peer in bridge.\n",
@@ -476,7 +480,7 @@ static int feature_automixmonitor(struct ast_bridge *bridge, struct ast_bridge_c
 }
 
 /*! \brief Internal built in feature for hangup */
-static int feature_hangup(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int feature_hangup(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	/*
 	 * This is very simple, we simply change the state on the
diff --git a/bridges/bridge_builtin_interval_features.c b/bridges/bridge_builtin_interval_features.c
index 4a091126b..6b8e91b1e 100644
--- a/bridges/bridge_builtin_interval_features.c
+++ b/bridges/bridge_builtin_interval_features.c
@@ -50,7 +50,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/stringfields.h"
 #include "asterisk/musiconhold.h"
 
-static int bridge_features_duration_callback(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int bridge_features_duration_callback(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct ast_bridge_features_limits *limits = hook_pvt;
 
@@ -110,7 +110,7 @@ static void limits_interval_playback(struct ast_bridge_channel *bridge_channel,
 	}
 }
 
-static int bridge_features_connect_callback(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int bridge_features_connect_callback(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct ast_bridge_features_limits *limits = hook_pvt;
 
@@ -118,7 +118,7 @@ static int bridge_features_connect_callback(struct ast_bridge *bridge, struct as
 	return -1;
 }
 
-static int bridge_features_warning_callback(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int bridge_features_warning_callback(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct ast_bridge_features_limits *limits = hook_pvt;
 
diff --git a/include/asterisk/bridge_features.h b/include/asterisk/bridge_features.h
index 3a4fd9444..0a3a21ede 100644
--- a/include/asterisk/bridge_features.h
+++ b/include/asterisk/bridge_features.h
@@ -118,7 +118,6 @@ struct ast_bridge_channel;
 /*!
  * \brief Hook callback type
  *
- * \param bridge The bridge that the channel is part of
  * \param bridge_channel Channel executing the feature
  * \param hook_pvt Private data passed in when the hook was created
  *
@@ -131,7 +130,7 @@ struct ast_bridge_channel;
  * \retval 0 Keep the callback hook.
  * \retval -1 Remove the callback hook.
  */
-typedef int (*ast_bridge_hook_callback)(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt);
+typedef int (*ast_bridge_hook_callback)(struct ast_bridge_channel *bridge_channel, void *hook_pvt);
 
 /*!
  * \brief Hook pvt destructor callback
@@ -143,17 +142,19 @@ typedef void (*ast_bridge_hook_pvt_destructor)(void *hook_pvt);
 /*!
  * \brief Talking indicator callback
  *
- * \details This callback can be registered with the bridge in order
- * to receive updates on when a bridge_channel has started and stopped
- * talking
+ * \details
+ * This callback can be registered with the bridge channel in
+ * order to receive updates when the bridge_channel has started
+ * and stopped talking.
  *
  * \param bridge_channel Channel executing the feature
+ * \param hook_pvt Private data passed in when the hook was created
  * \param talking TRUE if the channel is now talking
  *
  * \retval 0 Keep the callback hook.
  * \retval -1 Remove the callback hook.
  */
-typedef int (*ast_bridge_talking_indicate_callback)(struct ast_bridge_channel *bridge_channel, void *pvt_data, int talking);
+typedef int (*ast_bridge_talking_indicate_callback)(struct ast_bridge_channel *bridge_channel, void *hook_pvt, int talking);
 
 enum ast_bridge_hook_remove_flags {
 	/*! The hook is removed when the channel is pulled from the bridge. */
@@ -357,6 +358,8 @@ int ast_bridge_features_unregister(enum ast_bridge_builtin_feature feature);
  * \brief Invoke a built in feature hook now.
  *
  * \param feature The feature to invoke
+ * \param bridge_channel Channel executing the feature
+ * \param hook_pvt Private data passed in when the hook was created
  *
  * \note This API call is only meant to be used by bridge
  * subclasses and hook callbacks to request a builtin feature
@@ -368,10 +371,10 @@ int ast_bridge_features_unregister(enum ast_bridge_builtin_feature feature);
  * Example usage:
  *
  * \code
- * ast_bridge_features_do(AST_BRIDGE_BUILTIN_ATTENDED_TRANSFER, bridge, bridge_channel, hook_pvt);
+ * ast_bridge_features_do(AST_BRIDGE_BUILTIN_ATTENDED_TRANSFER, bridge_channel, hook_pvt);
  * \endcode
  */
-int ast_bridge_features_do(enum ast_bridge_builtin_feature feature, struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt);
+int ast_bridge_features_do(enum ast_bridge_builtin_feature feature, struct ast_bridge_channel *bridge_channel, void *hook_pvt);
 
 /*!
  * \brief Attach interval hooks to a bridge features structure
diff --git a/include/asterisk/parking.h b/include/asterisk/parking.h
index dd8a67bf2..4a721200a 100644
--- a/include/asterisk/parking.h
+++ b/include/asterisk/parking.h
@@ -111,8 +111,7 @@ void ast_bridge_channel_park(struct ast_bridge_channel *bridge_channel,
 	const char *parker_uuid,
 	const char *app_data);
 
-typedef int (*ast_park_blind_xfer_fn)(struct ast_bridge *bridge, struct ast_bridge_channel *parker,
-	struct ast_exten *park_exten);
+typedef int (*ast_park_blind_xfer_fn)(struct ast_bridge_channel *parker, struct ast_exten *park_exten);
 
 /*!
  * \brief install a callback for handling blind transfers to a parking extension
@@ -132,15 +131,13 @@ void ast_uninstall_park_blind_xfer_func(void);
  * \brief use the installed park blind xfer func
  * \since 12
  *
- * \param bridge Bridge being transferred from
- * \param bridge_channel Bridge channel initiating the transfer
- * \param app_data arguments to the park application
+ * \param parker Bridge channel initiating the park
+ * \param park_exten Exten to blind transfer part to.
  *
  * \retval 0 on success
  * \retval -1 on failure
  */
-int ast_park_blind_xfer(struct ast_bridge *bridge, struct ast_bridge_channel *parker,
-		struct ast_exten *park_exten);
+int ast_park_blind_xfer(struct ast_bridge_channel *parker, struct ast_exten *park_exten);
 
 typedef void (*ast_bridge_channel_park_fn)(struct ast_bridge_channel *parkee, const char *parkee_uuid,
 	const char *parker_uuid, const char *app_data);
diff --git a/main/bridge.c b/main/bridge.c
index e3a00ed2e..0b4d95d5e 100644
--- a/main/bridge.c
+++ b/main/bridge.c
@@ -2675,7 +2675,7 @@ int ast_bridge_features_unregister(enum ast_bridge_builtin_feature feature)
 	return 0;
 }
 
-int ast_bridge_features_do(enum ast_bridge_builtin_feature feature, struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+int ast_bridge_features_do(enum ast_bridge_builtin_feature feature, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	ast_bridge_hook_callback callback;
 
@@ -2687,7 +2687,7 @@ int ast_bridge_features_do(enum ast_bridge_builtin_feature feature, struct ast_b
 	if (!callback) {
 		return -1;
 	}
-	callback(bridge, bridge_channel, hook_pvt);
+	callback(bridge_channel, hook_pvt);
 
 	return 0;
 }
@@ -3777,8 +3777,7 @@ enum try_parking_result {
 	PARKING_NOT_APPLICABLE,
 };
 
-static enum try_parking_result try_parking(struct ast_bridge *bridge, struct ast_channel *transferer,
-		const char *exten, const char *context)
+static enum try_parking_result try_parking(struct ast_channel *transferer, const char *exten, const char *context)
 {
 	RAII_VAR(struct ast_bridge_channel *, transferer_bridge_channel, NULL, ao2_cleanup);
 	struct ast_exten *parking_exten;
@@ -3793,7 +3792,7 @@ static enum try_parking_result try_parking(struct ast_bridge *bridge, struct ast
 
 	parking_exten = ast_get_parking_exten(exten, NULL, context);
 	if (parking_exten) {
-		return ast_park_blind_xfer(bridge, transferer_bridge_channel, parking_exten) == 0 ?
+		return ast_park_blind_xfer(transferer_bridge_channel, parking_exten) == 0 ?
 			PARKING_SUCCESS : PARKING_FAILURE;
 	}
 
@@ -3871,7 +3870,7 @@ enum ast_transfer_result ast_bridge_transfer_blind(int is_external,
 	RAII_VAR(struct ast_bridge *, bridge, NULL, ao2_cleanup);
 	RAII_VAR(struct ast_bridge_channel *, bridge_channel, NULL, ao2_cleanup);
 	RAII_VAR(struct ao2_container *, channels, NULL, ao2_cleanup);
-	RAII_VAR(struct ast_channel *, transferee, NULL, ao2_cleanup);
+	RAII_VAR(struct ast_channel *, transferee, NULL, ast_channel_cleanup);
 	int do_bridge_transfer;
 	int transfer_prohibited;
 	enum try_parking_result parking_result;
@@ -3893,7 +3892,7 @@ enum ast_transfer_result ast_bridge_transfer_blind(int is_external,
 	/* Take off hold if they are on hold. */
 	ast_bridge_channel_write_unhold(bridge_channel);
 
-	parking_result = try_parking(bridge, transferer, exten, context);
+	parking_result = try_parking(transferer, exten, context);
 	switch (parking_result) {
 	case PARKING_SUCCESS:
 		transfer_result = AST_BRIDGE_TRANSFER_SUCCESS;
diff --git a/main/bridge_basic.c b/main/bridge_basic.c
index 7eaf30eb9..10c4efb57 100644
--- a/main/bridge_basic.c
+++ b/main/bridge_basic.c
@@ -265,20 +265,19 @@ struct ast_flags *ast_bridge_features_ds_get(struct ast_channel *chan)
  * \brief Determine if we should dissolve the bridge from a hangup.
  * \since 12.0.0
  *
- * \param bridge The bridge that the channel is part of
  * \param bridge_channel Channel executing the feature
  * \param hook_pvt Private data passed in when the hook was created
  *
  * \retval 0 Keep the callback hook.
  * \retval -1 Remove the callback hook.
  */
-static int basic_hangup_hook(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int basic_hangup_hook(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	int bridge_count = 0;
 	struct ast_bridge_channel *iter;
 
 	ast_bridge_channel_lock_bridge(bridge_channel);
-	AST_LIST_TRAVERSE(&bridge->channels, iter, entry) {
+	AST_LIST_TRAVERSE(&bridge_channel->bridge->channels, iter, entry) {
 		if (iter != bridge_channel && iter->state == BRIDGE_CHANNEL_STATE_WAIT) {
 			++bridge_count;
 		}
@@ -1069,7 +1068,6 @@ static const char *get_transfer_context(struct ast_channel *transferer, const ch
 /*!
  * \brief Allocate and initialize attended transfer properties
  *
- * \param transferee_bridge The bridge where the transfer was initiated
  * \param transferer The channel performing the attended transfer
  * \param context Suggestion for what context the transfer target extension can be found in
  *
@@ -1077,8 +1075,7 @@ static const char *get_transfer_context(struct ast_channel *transferer, const ch
  * \retval non-NULL Newly allocated properties
  */
 static struct attended_transfer_properties *attended_transfer_properties_alloc(
-		struct ast_bridge *transferee_bridge, struct ast_channel *transferer,
-		const char *context)
+	struct ast_channel *transferer, const char *context)
 {
 	struct attended_transfer_properties *props;
 	char *tech;
@@ -1162,9 +1159,9 @@ static void attended_transfer_properties_shutdown(struct attended_transfer_prope
 	ast_debug(1, "Shutting down attended transfer %p\n", props);
 
 	if (props->transferee_bridge) {
-		ast_bridge_merge_inhibit(props->transferee_bridge, -1);
 		bridge_basic_change_personality(props->transferee_bridge,
 				BRIDGE_BASIC_PERSONALITY_NORMAL, NULL);
+		ast_bridge_merge_inhibit(props->transferee_bridge, -1);
 	}
 
 	if (props->target_bridge) {
@@ -2145,7 +2142,7 @@ static int fail_enter(struct attended_transfer_properties *props)
  *
  * Sends a stimulus to the attended transfer monitor thread that the abort sequence has been pressed
  */
-static int atxfer_abort(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int atxfer_abort(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct attended_transfer_properties *props = hook_pvt;
 
@@ -2159,7 +2156,7 @@ static int atxfer_abort(struct ast_bridge *bridge, struct ast_bridge_channel *br
  *
  * Sends a stimulus to the attended transfer monitor thread that the complete sequence has been pressed
  */
-static int atxfer_complete(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int atxfer_complete(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct attended_transfer_properties *props = hook_pvt;
 
@@ -2173,7 +2170,7 @@ static int atxfer_complete(struct ast_bridge *bridge, struct ast_bridge_channel
  *
  * Sends a stimulus to the attended transfer monitor thread that the threeway sequence has been pressed
  */
-static int atxfer_threeway(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int atxfer_threeway(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct attended_transfer_properties *props = hook_pvt;
 
@@ -2187,7 +2184,7 @@ static int atxfer_threeway(struct ast_bridge *bridge, struct ast_bridge_channel
  *
  * Sends a stimulus to the attended transfer monitor thread that the swap sequence has been pressed
  */
-static int atxfer_swap(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int atxfer_swap(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct attended_transfer_properties *props = hook_pvt;
 
@@ -2201,7 +2198,7 @@ static int atxfer_swap(struct ast_bridge *bridge, struct ast_bridge_channel *bri
  *
  * Sends a stimulus to the attended transfer monitor thread that the transferer has hung up.
  */
-static int atxfer_transferer_hangup(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int atxfer_transferer_hangup(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct attended_transfer_properties *props = hook_pvt;
 
@@ -2622,48 +2619,64 @@ static struct ast_channel *dial_transfer(struct ast_channel *caller, const char
  * an attended transfer. For more information about attended transfer
  * progress, see documentation on the transfer state machine.
  *
- * \param bridge Bridge where attended transfer DTMF sequence was entered
  * \param bridge_channel The channel that pressed the attended transfer DTMF sequence
  * \param hook_pvt Structure with further information about the attended transfer
  */
-static int feature_attended_transfer(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int feature_attended_transfer(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct ast_bridge_features_attended_transfer *attended_transfer = hook_pvt;
 	struct attended_transfer_properties *props;
+	struct ast_bridge *bridge;
 	char destination[AST_MAX_EXTENSION + AST_MAX_CONTEXT + 1];
 	char exten[AST_MAX_EXTENSION] = "";
 	pthread_t thread;
 
+	/* Inhibit the bridge before we do anything else. */
+	bridge = ast_bridge_channel_merge_inhibit(bridge_channel, +1);
+
 	if (strcmp(bridge->v_table->name, "basic")) {
-		ast_log(LOG_ERROR, "Attended transfer attempted on unsupported bridge type '%s'\n", bridge->v_table->name);
+		ast_log(LOG_ERROR, "Attended transfer attempted on unsupported bridge type '%s'.\n",
+			bridge->v_table->name);
+		ast_bridge_merge_inhibit(bridge, -1);
+		ao2_ref(bridge, -1);
 		return 0;
 	}
 
-	if (bridge->inhibit_merge) {
-		ast_log(LOG_ERROR, "Unable to perform attended transfer since bridge '%s' does not permit merging.\n", bridge->uniqueid);
+	/* Was the bridge inhibited before we inhibited it? */
+	if (1 < bridge->inhibit_merge) {
+		/*
+		 * The peer likely initiated attended transfer at the same time
+		 * and we lost the race.
+		 */
+		ast_verb(3, "Channel %s: Bridge '%s' does not permit merging at this time.\n",
+			ast_channel_name(bridge_channel->chan), bridge->uniqueid);
+		ast_bridge_merge_inhibit(bridge, -1);
+		ao2_ref(bridge, -1);
 		return 0;
 	}
 
-	props = attended_transfer_properties_alloc(bridge, bridge_channel->chan,
-			attended_transfer ? attended_transfer->context : NULL);
-
+	props = attended_transfer_properties_alloc(bridge_channel->chan,
+		attended_transfer ? attended_transfer->context : NULL);
 	if (!props) {
-		ast_log(LOG_ERROR, "Unable to allocate control structure for performing attended transfer\n");
+		ast_log(LOG_ERROR, "Unable to allocate control structure for performing attended transfer.\n");
+		ast_bridge_merge_inhibit(bridge, -1);
+		ao2_ref(bridge, -1);
 		return 0;
 	}
 
+	props->transferee_bridge = bridge;
+
 	if (add_transferer_role(props->transferer, attended_transfer)) {
-		ast_log(LOG_ERROR, "Unable to set transferer bridge role properly\n");
+		ast_log(LOG_ERROR, "Unable to set transferrer bridge role.\n");
 		attended_transfer_properties_shutdown(props);
 		return 0;
 	}
 
 	ast_bridge_channel_write_hold(bridge_channel, NULL);
-	props->transferee_bridge = ast_bridge_channel_merge_inhibit(bridge_channel, +1);
 
 	/* Grab the extension to transfer to */
 	if (grab_transfer(bridge_channel->chan, exten, sizeof(exten), props->context)) {
-		ast_log(LOG_WARNING, "Unable to acquire target extension for attended transfer\n");
+		ast_log(LOG_WARNING, "Unable to acquire target extension for attended transfer.\n");
 		ast_bridge_channel_write_unhold(bridge_channel);
 		attended_transfer_properties_shutdown(props);
 		return 0;
@@ -2679,7 +2692,7 @@ static int feature_attended_transfer(struct ast_bridge *bridge, struct ast_bridg
 	/* Get a channel that is the destination we wish to call */
 	props->transfer_target = dial_transfer(bridge_channel->chan, destination);
 	if (!props->transfer_target) {
-		ast_log(LOG_ERROR, "Unable to request outbound channel for attended transfer target\n");
+		ast_log(LOG_ERROR, "Unable to request outbound channel for attended transfer target.\n");
 		ast_stream_and_wait(props->transferer, props->failsound, AST_DIGIT_NONE);
 		ast_bridge_channel_write_unhold(bridge_channel);
 		attended_transfer_properties_shutdown(props);
@@ -2690,7 +2703,7 @@ static int feature_attended_transfer(struct ast_bridge *bridge, struct ast_bridg
 	/* Create a bridge to use to talk to the person we are calling */
 	props->target_bridge = ast_bridge_basic_new();
 	if (!props->target_bridge) {
-		ast_log(LOG_ERROR, "Unable to create bridge for attended transfer target\n");
+		ast_log(LOG_ERROR, "Unable to create bridge for attended transfer target.\n");
 		ast_stream_and_wait(props->transferer, props->failsound, AST_DIGIT_NONE);
 		ast_bridge_channel_write_unhold(bridge_channel);
 		ast_hangup(props->transfer_target);
@@ -2701,7 +2714,7 @@ static int feature_attended_transfer(struct ast_bridge *bridge, struct ast_bridg
 	ast_bridge_merge_inhibit(props->target_bridge, +1);
 
 	if (attach_framehook(props, props->transfer_target)) {
-		ast_log(LOG_ERROR, "Unable to attach framehook to transfer target\n");
+		ast_log(LOG_ERROR, "Unable to attach framehook to transfer target.\n");
 		ast_stream_and_wait(props->transferer, props->failsound, AST_DIGIT_NONE);
 		ast_bridge_channel_write_unhold(bridge_channel);
 		ast_hangup(props->transfer_target);
@@ -2716,7 +2729,7 @@ static int feature_attended_transfer(struct ast_bridge *bridge, struct ast_bridg
 			BRIDGE_BASIC_PERSONALITY_ATXFER, props);
 
 	if (ast_call(props->transfer_target, destination, 0)) {
-		ast_log(LOG_ERROR, "Unable to place outbound call to transfer target\n");
+		ast_log(LOG_ERROR, "Unable to place outbound call to transfer target.\n");
 		ast_stream_and_wait(bridge_channel->chan, props->failsound, AST_DIGIT_NONE);
 		ast_bridge_channel_write_unhold(bridge_channel);
 		ast_hangup(props->transfer_target);
@@ -2731,16 +2744,17 @@ static int feature_attended_transfer(struct ast_bridge *bridge, struct ast_bridg
 	 */
 	ast_channel_ref(props->transfer_target);
 	if (ast_bridge_impart(props->target_bridge, props->transfer_target, NULL, NULL, 1)) {
-		ast_log(LOG_ERROR, "Unable to place transfer target into bridge\n");
+		ast_log(LOG_ERROR, "Unable to place transfer target into bridge.\n");
 		ast_stream_and_wait(bridge_channel->chan, props->failsound, AST_DIGIT_NONE);
 		ast_bridge_channel_write_unhold(bridge_channel);
 		ast_hangup(props->transfer_target);
+		props->transfer_target = NULL;
 		attended_transfer_properties_shutdown(props);
 		return 0;
 	}
 
 	if (ast_pthread_create_detached(&thread, NULL, attended_transfer_monitor_thread, props)) {
-		ast_log(LOG_ERROR, "Unable to create monitoring thread for attended transfer\n");
+		ast_log(LOG_ERROR, "Unable to create monitoring thread for attended transfer.\n");
 		ast_stream_and_wait(bridge_channel->chan, props->failsound, AST_DIGIT_NONE);
 		ast_bridge_channel_write_unhold(bridge_channel);
 		attended_transfer_properties_shutdown(props);
@@ -2764,18 +2778,13 @@ static void blind_transfer_cb(struct ast_channel *new_channel, void *user_data,
 }
 
 /*! \brief Internal built in feature for blind transfers */
-static int feature_blind_transfer(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int feature_blind_transfer(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	char exten[AST_MAX_EXTENSION] = "";
 	struct ast_bridge_features_blind_transfer *blind_transfer = hook_pvt;
 	const char *context;
 	char *goto_on_blindxfr;
 
-	if (strcmp(bridge->v_table->name, "basic")) {
-		ast_log(LOG_ERROR, "Blind transfer attempted on unsupported bridge type '%s'\n", bridge->v_table->name);
-		return 0;
-	}
-
 	ast_bridge_channel_write_hold(bridge_channel, NULL);
 
 	ast_channel_lock(bridge_channel->chan);
diff --git a/main/bridge_channel.c b/main/bridge_channel.c
index cec3d1ad1..f887ef576 100644
--- a/main/bridge_channel.c
+++ b/main/bridge_channel.c
@@ -283,7 +283,7 @@ static void bridge_channel_handle_hangup(struct ast_bridge_channel *bridge_chann
 		if (hook->type != AST_BRIDGE_HOOK_TYPE_HANGUP) {
 			continue;
 		}
-		remove_me = hook->callback(bridge_channel->bridge, bridge_channel, hook->hook_pvt);
+		remove_me = hook->callback(bridge_channel, hook->hook_pvt);
 		if (remove_me) {
 			ast_debug(1, "Hangup hook %p is being removed from %p(%s)\n",
 				hook, bridge_channel, ast_channel_name(bridge_channel->chan));
@@ -916,8 +916,7 @@ static void bridge_channel_handle_interval(struct ast_bridge_channel *bridge_cha
 
 		ast_debug(1, "Executing hook %p on %p(%s)\n",
 			hook, bridge_channel, ast_channel_name(bridge_channel->chan));
-		interval = hook->generic.callback(bridge_channel->bridge, bridge_channel,
-			hook->generic.hook_pvt);
+		interval = hook->generic.callback(bridge_channel, hook->generic.hook_pvt);
 
 		ast_heap_wrlock(interval_hooks);
 		if (ast_heap_peek(interval_hooks, hook->timer.heap_index) != hook
@@ -1053,8 +1052,7 @@ static void bridge_channel_feature(struct ast_bridge_channel *bridge_channel)
 	if (hook) {
 		int remove_me;
 
-		remove_me = hook->generic.callback(bridge_channel->bridge, bridge_channel,
-			hook->generic.hook_pvt);
+		remove_me = hook->generic.callback(bridge_channel, hook->generic.hook_pvt);
 		if (remove_me) {
 			ast_debug(1, "DTMF hook %p is being removed from %p(%s)\n",
 				hook, bridge_channel, ast_channel_name(bridge_channel->chan));
@@ -1782,7 +1780,7 @@ static void bridge_channel_event_join_leave(struct ast_bridge_channel *bridge_ch
 		ast_indicate(bridge_channel->chan, AST_CONTROL_SRCUPDATE);
 		do {
 			if (hook->type == type) {
-				hook->callback(bridge_channel->bridge, bridge_channel, hook->hook_pvt);
+				hook->callback(bridge_channel, hook->hook_pvt);
 				ao2_unlink(features->other_hooks, hook);
 			}
 			ao2_ref(hook, -1);
diff --git a/main/features.c b/main/features.c
index 417f18c66..56e47fb91 100644
--- a/main/features.c
+++ b/main/features.c
@@ -1842,14 +1842,13 @@ struct dynamic_dtmf_hook_data {
  * \brief Activated dynamic DTMF feature hook.
  * \since 12.0.0
  *
- * \param bridge The bridge that the channel is part of
  * \param bridge_channel Channel executing the feature
  * \param hook_pvt Private data passed in when the hook was created
  *
  * \retval 0 Keep the callback hook.
  * \retval -1 Remove the callback hook.
  */
-static int dynamic_dtmf_hook_trip(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int dynamic_dtmf_hook_trip(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct dynamic_dtmf_hook_data *pvt = hook_pvt;
 	int (*run_it)(struct ast_bridge_channel *bridge_channel, ast_bridge_custom_callback_fn callback, const void *payload, size_t payload_size);
diff --git a/main/parking.c b/main/parking.c
index 820cffdea..710a3c8c7 100644
--- a/main/parking.c
+++ b/main/parking.c
@@ -147,12 +147,12 @@ void ast_uninstall_bridge_channel_park_func(void)
 	ast_bridge_channel_park_func = NULL;
 }
 
-int ast_park_blind_xfer(struct ast_bridge *bridge, struct ast_bridge_channel *parker,
-		struct ast_exten *park_exten)
+int ast_park_blind_xfer(struct ast_bridge_channel *parker, struct ast_exten *park_exten)
 {
 	static int warned = 0;
+
 	if (ast_park_blind_xfer_func) {
-		return ast_park_blind_xfer_func(bridge, parker, park_exten);
+		return ast_park_blind_xfer_func(parker, park_exten);
 	}
 
 	if (warned++ % 10 == 0) {
diff --git a/res/parking/parking_bridge_features.c b/res/parking/parking_bridge_features.c
index 1d9e3dada..e44a7695b 100644
--- a/res/parking/parking_bridge_features.c
+++ b/res/parking/parking_bridge_features.c
@@ -183,7 +183,7 @@ static int create_parked_subscription(struct ast_channel *chan, const char *park
 /*!
  * \internal
  * \brief Helper function that creates an outgoing channel and returns it immediately. This function is nearly
- *        identical to the dial_transfer function in bridge_builtin_features.c, however it doesn't swap the
+ *        identical to the dial_transfer function in bridge_basic.c, however it doesn't swap the
  *        local channel and the channel that instigated the park.
  */
 static struct ast_channel *park_local_transfer(struct ast_channel *parker, const char *exten, const char *context)
@@ -242,7 +242,7 @@ static struct ast_channel *park_local_transfer(struct ast_channel *parker, const
 	return parkee;
 }
 
-static int park_feature_helper(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, struct ast_exten *park_exten)
+static int park_feature_helper(struct ast_bridge_channel *bridge_channel, struct ast_exten *park_exten)
 {
 	RAII_VAR(struct ast_channel *, other, NULL, ao2_cleanup);
 	RAII_VAR(struct parking_lot *, lot, NULL, ao2_cleanup);
@@ -251,7 +251,9 @@ static int park_feature_helper(struct ast_bridge *bridge, struct ast_bridge_chan
 	RAII_VAR(struct ao2_container *, bridge_peers, NULL, ao2_cleanup);
 	struct ao2_iterator iter;
 
-	bridge_peers = ast_bridge_peers(bridge);
+	ast_bridge_channel_lock_bridge(bridge_channel);
+	bridge_peers = ast_bridge_peers_nolock(bridge_channel->bridge);
+	ast_bridge_unlock(bridge_channel->bridge);
 
 	if (ao2_container_count(bridge_peers) < 2) {
 		/* There is nothing to do if there is no one to park. */
@@ -357,20 +359,19 @@ static void park_bridge_channel(struct ast_bridge_channel *bridge_channel, const
 	}
 }
 
-static int feature_park(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int feature_park(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
-	park_feature_helper(bridge, bridge_channel, NULL);
+	park_feature_helper(bridge_channel, NULL);
 	return 0;
 }
 
 /*! \internal
  * \brief Interval hook. Pulls a parked call from the parking bridge after the timeout is passed and sets the resolution to timeout.
  *
- * \param bridge Which bridge the channel was parked in
  * \param bridge_channel bridge channel this interval hook is being executed on
  * \param hook_pvt A pointer to the parked_user struct associated with the channel is stuffed in here
  */
-static int parking_duration_callback(struct ast_bridge *bridge, struct ast_bridge_channel *bridge_channel, void *hook_pvt)
+static int parking_duration_callback(struct ast_bridge_channel *bridge_channel, void *hook_pvt)
 {
 	struct parked_user *user = hook_pvt;
 	struct ast_channel *chan = user->chan;