[dm-devel] [PATCH 05/35] libmultipath: improve cleanup of uevent queues on exit

[mwilck at suse.com]

From: Martin Wilck <mwilck at suse.com>

uevents listed on merge_node must be cleaned up, too. uevents
cancelled while being serviced and temporary queues, likewise.
The global uevq must be cleaned out in the uevent listener thread,
because it might have added events after the dispatcher thread
had already finished.

Signed-off-by: Martin Wilck <mwilck at suse.com>
---
 libmultipath/uevent.c | 49 ++++++++++++++++++++++++++++++++-----------
 1 file changed, 37 insertions(+), 12 deletions(-)

diff --git a/libmultipath/uevent.c b/libmultipath/uevent.c
index 4265904..082e891 100644
--- a/libmultipath/uevent.c
+++ b/libmultipath/uevent.c
@@ -91,16 +91,25 @@ struct uevent * alloc_uevent (void)
 	return uev;
 }
 
+static void uevq_cleanup(struct list_head *tmpq);
+
+static void cleanup_uev(void *arg)
+{
+	struct uevent *uev = arg;
+
+	uevq_cleanup(&uev->merge_node);
+	if (uev->udev)
+		udev_device_unref(uev->udev);
+	FREE(uev);
+}
+
 static void uevq_cleanup(struct list_head *tmpq)
 {
 	struct uevent *uev, *tmp;
 
 	list_for_each_entry_safe(uev, tmp, tmpq, node) {
 		list_del_init(&uev->node);
-
-		if (uev->udev)
-			udev_device_unref(uev->udev);
-		FREE(uev);
+		cleanup_uev(uev);
 	}
 }
 
@@ -384,14 +393,10 @@ service_uevq(struct list_head *tmpq)
 	list_for_each_entry_safe(uev, tmp, tmpq, node) {
 		list_del_init(&uev->node);
 
+		pthread_cleanup_push(cleanup_uev, uev);
 		if (my_uev_trigger && my_uev_trigger(uev, my_trigger_data))
 			condlog(0, "uevent trigger error");
-
-		uevq_cleanup(&uev->merge_node);
-
-		if (uev->udev)
-			udev_device_unref(uev->udev);
-		FREE(uev);
+		pthread_cleanup_pop(1);
 	}
 }
 
@@ -411,6 +416,18 @@ static void monitor_cleanup(void *arg)
 	udev_monitor_unref(monitor);
 }
 
+static void cleanup_uevq(void *arg)
+{
+	uevq_cleanup(arg);
+}
+
+static void cleanup_global_uevq(void *arg __attribute__((unused)))
+{
+	pthread_mutex_lock(uevq_lockp);
+	uevq_cleanup(&uevq);
+	pthread_mutex_unlock(uevq_lockp);
+}
+
 /*
  * Service the uevent queue.
  */
@@ -425,6 +442,7 @@ int uevent_dispatch(int (*uev_trigger)(struct uevent *, void * trigger_data),
 	while (1) {
 		LIST_HEAD(uevq_tmp);
 
+		pthread_cleanup_push(cleanup_mutex, uevq_lockp);
 		pthread_mutex_lock(uevq_lockp);
 		servicing_uev = 0;
 		/*
@@ -436,14 +454,17 @@ int uevent_dispatch(int (*uev_trigger)(struct uevent *, void * trigger_data),
 		}
 		servicing_uev = 1;
 		list_splice_init(&uevq, &uevq_tmp);
-		pthread_mutex_unlock(uevq_lockp);
+		pthread_cleanup_pop(1);
+
 		if (!my_uev_trigger)
 			break;
+
+		pthread_cleanup_push(cleanup_uevq, &uevq_tmp);
 		merge_uevq(&uevq_tmp);
 		service_uevq(&uevq_tmp);
+		pthread_cleanup_pop(1);
 	}
 	condlog(3, "Terminating uev service queue");
-	uevq_cleanup(&uevq);
 	return 0;
 }
 
@@ -600,6 +621,8 @@ int uevent_listen(struct udev *udev)
 
 	events = 0;
 	gettimeofday(&start_time, NULL);
+	pthread_cleanup_push(cleanup_global_uevq, NULL);
+	pthread_cleanup_push(cleanup_uevq, &uevlisten_tmp);
 	while (1) {
 		struct uevent *uev;
 		struct udev_device *dev;
@@ -650,6 +673,8 @@ int uevent_listen(struct udev *udev)
 		gettimeofday(&start_time, NULL);
 		timeout = 30;
 	}
+	pthread_cleanup_pop(1);
+	pthread_cleanup_pop(1);
 out:
 	pthread_cleanup_pop(1);
 out_udev:
-- 
2.33.0