Merge "pjsip_scheduler.c: Fix some corner cases."

2 files changed, 120 insertions, 45 deletions

diff --git a/include/asterisk/res_pjsip.h b/include/asterisk/res_pjsip.h
index d3849ad34..b01d6f5d0 100644
--- a/include/asterisk/res_pjsip.h
+++ b/include/asterisk/res_pjsip.h
@@ -1407,7 +1407,7 @@ struct ast_sip_endpoint *ast_sip_get_artificial_endpoint(void);
  * the next item on the SIP socket(s) can be serviced. On incoming messages,
  * Asterisk automatically will push the request to a servant thread. When your
  * module callback is called, processing will already be in a servant. However,
- * for other PSJIP events, such as transaction state changes due to timer
+ * for other PJSIP events, such as transaction state changes due to timer
  * expirations, your module will be called into from a PJSIP thread. If you
  * are called into from a PJSIP thread, then you should push whatever processing
  * is needed to a servant as soon as possible. You can discern if you are currently
@@ -1588,13 +1588,13 @@ enum ast_sip_scheduler_task_flags {
 
 	/*!
 	 * Run at a fixed interval.
-	 * Stop scheduling if the callback returns 0.
+	 * Stop scheduling if the callback returns <= 0.
 	 * Any other value is ignored.
 	 */
 	AST_SIP_SCHED_TASK_FIXED = (0 << 0),
 	/*!
 	 * Run at a variable interval.
-	 * Stop scheduling if the callback returns 0.
+	 * Stop scheduling if the callback returns <= 0.
 	 * Any other return value is used as the new interval.
 	 */
 	AST_SIP_SCHED_TASK_VARIABLE = (1 << 0),
diff --git a/res/res_pjsip/pjsip_scheduler.c b/res/res_pjsip/pjsip_scheduler.c
index 75945be77..2b072b67e 100644
--- a/res/res_pjsip/pjsip_scheduler.c
+++ b/res/res_pjsip/pjsip_scheduler.c
@@ -28,6 +28,7 @@
 #include "asterisk/res_pjsip.h"
 #include "include/res_pjsip_private.h"
 #include "asterisk/res_pjsip_cli.h"
+#include "asterisk/taskprocessor.h"
 
 #define TASK_BUCKETS 53
 
@@ -36,30 +37,30 @@ static struct ao2_container *tasks;
 static int task_count;
 
 struct ast_sip_sched_task {
-	/*! ast_sip_sched task id */
-	uint32_t task_id;
-	/*! ast_sched scheudler id */
-	int current_scheduler_id;
-	/*! task is currently running */
-	int is_running;
-	/*! task */
-	ast_sip_task task;
+	/*! The serializer to be used (if any) (Holds a ref) */
+	struct ast_taskprocessor *serializer;
 	/*! task data */
 	void *task_data;
-	/*! reschedule interval in milliseconds */
-	int interval;
-	/*! the time the task was queued */
+	/*! task function */
+	ast_sip_task task;
+	/*! the time the task was originally scheduled/queued */
 	struct timeval when_queued;
 	/*! the last time the task was started */
 	struct timeval last_start;
 	/*! the last time the task was ended */
 	struct timeval last_end;
+	/*! When the periodic task is next expected to run */
+	struct timeval next_periodic;
+	/*! reschedule interval in milliseconds */
+	int interval;
+	/*! ast_sched scheudler id */
+	int current_scheduler_id;
+	/*! task is currently running */
+	int is_running;
 	/*! times run */
 	int run_count;
 	/*! the task reschedule, cleanup and policy flags */
 	enum ast_sip_scheduler_task_flags flags;
-	/*! the serializer to be used (if any) */
-	struct ast_taskprocessor *serializer;
 	/*! A name to be associated with the task */
 	char name[0];
 };
@@ -76,14 +77,19 @@ static int push_to_serializer(const void *data);
  */
 static int run_task(void *data)
 {
-	RAII_VAR(struct ast_sip_sched_task *, schtd, ao2_bump(data), ao2_cleanup);
+	RAII_VAR(struct ast_sip_sched_task *, schtd, data, ao2_cleanup);
 	int res;
 	int delay;
 
+	if (!schtd->interval) {
+		/* Task was cancelled while waiting to be executed by the serializer */
+		return -1;
+	}
+
 	ao2_lock(schtd);
 	schtd->last_start = ast_tvnow();
 	schtd->is_running = 1;
-	schtd->run_count++;
+	++schtd->run_count;
 	ao2_unlock(schtd);
 
 	res = schtd->task(schtd->task_data);
@@ -93,10 +99,10 @@ static int run_task(void *data)
 	schtd->last_end = ast_tvnow();
 
 	/*
-	 * Don't restart if the task returned 0 or if the interval
+	 * Don't restart if the task returned <= 0 or if the interval
 	 * was set to 0 while the task was running
 	 */
-	if (!res || !schtd->interval) {
+	if (res <= 0 || !schtd->interval) {
 		schtd->interval = 0;
 		ao2_unlock(schtd);
 		ao2_unlink(tasks, schtd);
@@ -110,13 +116,22 @@ static int run_task(void *data)
 	if (schtd->flags & AST_SIP_SCHED_TASK_DELAY) {
 		delay = schtd->interval;
 	} else {
-		delay = schtd->interval - (ast_tvdiff_ms(schtd->last_end, schtd->last_start) % schtd->interval);
+		int64_t diff;
+
+		/* Determine next periodic interval we need to expire. */
+		do {
+			schtd->next_periodic = ast_tvadd(schtd->next_periodic,
+				ast_samp2tv(schtd->interval, 1000));
+			diff = ast_tvdiff_ms(schtd->next_periodic, schtd->last_end);
+		} while (diff <= 0);
+		delay = diff;
 	}
 
 	schtd->current_scheduler_id = ast_sched_add(scheduler_context, delay, push_to_serializer, schtd);
 	if (schtd->current_scheduler_id < 0) {
 		schtd->interval = 0;
 		ao2_unlock(schtd);
+		ast_log(LOG_ERROR, "Sched %p: Failed to reschedule task %s\n", schtd, schtd->name);
 		ao2_unlink(tasks, schtd);
 		return -1;
 	}
@@ -133,9 +148,29 @@ static int run_task(void *data)
 static int push_to_serializer(const void *data)
 {
 	struct ast_sip_sched_task *schtd = (struct ast_sip_sched_task *)data;
+	int sched_id;
 
+	ao2_lock(schtd);
+	sched_id = schtd->current_scheduler_id;
+	schtd->current_scheduler_id = -1;
+	ao2_unlock(schtd);
+	if (sched_id < 0) {
+		/* Task was cancelled while waiting on the lock */
+		return 0;
+	}
+
+	ao2_t_ref(schtd, +1, "Give ref to run_task()");
 	if (ast_sip_push_task(schtd->serializer, run_task, schtd)) {
-		ao2_ref(schtd, -1);
+		/*
+		 * Oh my.  Have to cancel the scheduled item because we
+		 * unexpectedly cannot run it anymore.
+		 */
+		ao2_unlink(tasks, schtd);
+		ao2_lock(schtd);
+		schtd->interval = 0;
+		ao2_unlock(schtd);
+
+		ao2_t_ref(schtd, -1, "Failed so release run_task() ref");
 	}
 
 	return 0;
@@ -144,20 +179,22 @@ static int push_to_serializer(const void *data)
 int ast_sip_sched_task_cancel(struct ast_sip_sched_task *schtd)
 {
 	int res;
+	int sched_id;
 
-	if (!ao2_ref_and_lock(schtd)) {
-		return -1;
-	}
+	/*
+	 * Prevent any tasks in the serializer queue from
+	 * running and restarting the scheduled item on us
+	 * first.
+	 */
+	ao2_lock(schtd);
+	schtd->interval = 0;
 
-	if (schtd->current_scheduler_id < 0 || schtd->interval <= 0) {
-		ao2_unlock_and_unref(schtd);
-		return 0;
-	}
+	sched_id = schtd->current_scheduler_id;
+	schtd->current_scheduler_id = -1;
+	ao2_unlock(schtd);
+	res = ast_sched_del(scheduler_context, sched_id);
 
-	schtd->interval = 0;
-	ao2_unlock_and_unref(schtd);
 	ao2_unlink(tasks, schtd);
-	res = ast_sched_del(scheduler_context, schtd->current_scheduler_id);
 
 	return res;
 }
@@ -306,7 +343,7 @@ int ast_sip_sched_is_task_running_by_name(const char *name)
 	return is_running;
 }
 
-static void schtd_destructor(void *data)
+static void schtd_dtor(void *data)
 {
 	struct ast_sip_sched_task *schtd = data;
 
@@ -316,6 +353,7 @@ static void schtd_destructor(void *data)
 	} else if (schtd->task_data && (schtd->flags & AST_SIP_SCHED_TASK_DATA_FREE)) {
 		ast_free(schtd->task_data);
 	}
+	ast_taskprocessor_unreference(schtd->serializer);
 }
 
 struct ast_sip_sched_task *ast_sip_schedule_task(struct ast_taskprocessor *serializer,
@@ -326,38 +364,60 @@ struct ast_sip_sched_task *ast_sip_schedule_task(struct ast_taskprocessor *seria
 	struct ast_sip_sched_task *schtd;
 	int res;
 
-	if (interval < 0) {
+	if (interval <= 0) {
 		return NULL;
 	}
 
-	schtd = ao2_alloc((sizeof(*schtd) + (!ast_strlen_zero(name) ? strlen(name) : ID_LEN) + 1), schtd_destructor);
+	schtd = ao2_alloc((sizeof(*schtd) + (!ast_strlen_zero(name) ? strlen(name) : ID_LEN) + 1),
+		schtd_dtor);
 	if (!schtd) {
 		return NULL;
 	}
 
-	schtd->task_id = ast_atomic_fetchadd_int(&task_count, 1);
-	schtd->serializer = serializer;
+	schtd->serializer = ao2_bump(serializer);
+	schtd->task_data = task_data;
 	schtd->task = sip_task;
+	schtd->interval = interval;
+	schtd->flags = flags;
 	if (!ast_strlen_zero(name)) {
 		strcpy(schtd->name, name); /* Safe */
 	} else {
-		sprintf(schtd->name, "task_%08x", schtd->task_id);
+		uint32_t task_id;
+
+		task_id = ast_atomic_fetchadd_int(&task_count, 1);
+		sprintf(schtd->name, "task_%08x", task_id);
 	}
-	schtd->task_data = task_data;
-	schtd->flags = flags;
-	schtd->interval = interval;
 	schtd->when_queued = ast_tvnow();
+	if (!(schtd->flags & AST_SIP_SCHED_TASK_DELAY)) {
+		schtd->next_periodic = ast_tvadd(schtd->when_queued,
+			ast_samp2tv(schtd->interval, 1000));
+	}
 
 	if (flags & AST_SIP_SCHED_TASK_DATA_AO2) {
 		ao2_ref(task_data, +1);
 	}
+
+	/*
+	 * We must put it in the 'tasks' container before scheduling
+	 * the task because we don't want the push_to_serializer()
+	 * sched task to "remove" it on failure before we even put
+	 * it in.  If this happens then nothing would remove it from
+	 * the 'tasks' container.
+	 */
+	ao2_link(tasks, schtd);
+
+	/*
+	 * Lock so we are guaranteed to get the sched id set before
+	 * the push_to_serializer() sched task can clear it.
+	 */
+	ao2_lock(schtd);
 	res = ast_sched_add(scheduler_context, interval, push_to_serializer, schtd);
+	schtd->current_scheduler_id = res;
+	ao2_unlock(schtd);
 	if (res < 0) {
+		ao2_unlink(tasks, schtd);
 		ao2_ref(schtd, -1);
 		return NULL;
-	} else {
-		schtd->current_scheduler_id = res;
-		ao2_link(tasks, schtd);
 	}
 
 	return schtd;
@@ -470,7 +530,8 @@ static struct ast_cli_entry cli_commands[] = {
 
 int ast_sip_initialize_scheduler(void)
 {
-	if (!(scheduler_context = ast_sched_context_create())) {
+	scheduler_context = ast_sched_context_create();
+	if (!scheduler_context) {
 		ast_log(LOG_ERROR, "Failed to create scheduler. Aborting load\n");
 		return -1;
 	}
@@ -500,7 +561,21 @@ int ast_sip_destroy_scheduler(void)
 	ast_cli_unregister_multiple(cli_commands, ARRAY_LEN(cli_commands));
 
 	if (scheduler_context) {
+		if (tasks) {
+			struct ao2_iterator iter;
+			struct ast_sip_sched_task *schtd;
+
+			/* Cancel all scheduled tasks */
+			iter = ao2_iterator_init(tasks, 0);
+			while ((schtd = ao2_iterator_next(&iter))) {
+				ast_sip_sched_task_cancel(schtd);
+				ao2_ref(schtd, -1);
+			}
+			ao2_iterator_destroy(&iter);
+		}
+
 		ast_sched_context_destroy(scheduler_context);
+		scheduler_context = NULL;
 	}
 
 	ao2_cleanup(tasks);