device-mapper-multipath/0042-multipathd-move-vecs-desctruction-into-cleanup-funct.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Martin Wilck <mwilck@suse.com>
Date: Wed, 23 Sep 2020 18:05:40 +0200
Subject: [PATCH] multipathd: move vecs desctruction into cleanup function

This will make it easer to move the stuff around later.
The only functional change is that map destuction now happens after
joining all threads, which should actually improve robustness.

Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 multipathd/main.c | 64 +++++++++++++++++++++++++++++------------------
 1 file changed, 40 insertions(+), 24 deletions(-)

diff --git a/multipathd/main.c b/multipathd/main.c
index abc6a9f7..3da0d7cc 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -148,7 +148,7 @@ int should_exit(void)
 /*
  * global copy of vecs for use in sig handlers
  */
-struct vectors * gvecs;
+static struct vectors * gvecs;
 
 struct config *multipath_conf;
 
@@ -2889,6 +2889,44 @@ set_oom_adj (void)
 	condlog(0, "couldn't adjust oom score");
 }
 
+static void cleanup_maps(struct vectors *vecs)
+{
+	int queue_without_daemon, i;
+	struct multipath *mpp;
+	struct config *conf;
+
+	conf = get_multipath_config();
+	queue_without_daemon = conf->queue_without_daemon;
+	put_multipath_config(conf);
+	if (queue_without_daemon == QUE_NO_DAEMON_OFF)
+		vector_foreach_slot(vecs->mpvec, mpp, i)
+			dm_queue_if_no_path(mpp->alias, 0);
+	remove_maps_and_stop_waiters(vecs);
+	vecs->mpvec = NULL;
+}
+
+static void cleanup_paths(struct vectors *vecs)
+{
+	free_pathvec(vecs->pathvec, FREE_PATHS);
+	vecs->pathvec = NULL;
+}
+
+static void cleanup_vecs(void)
+{
+	if (!gvecs)
+		return;
+	/*
+	 * We can't take the vecs lock here, because exit() may
+	 * have been called from the child() thread, holding the lock already.
+	 * Anyway, by the time we get here, all threads that might access
+	 * vecs should have been joined already (in cleanup_threads).
+	 */
+	cleanup_maps(gvecs);
+	cleanup_paths(gvecs);
+	pthread_mutex_destroy(&gvecs->lock.mutex);
+	FREE(gvecs);
+}
+
 /*
  * Use a non-default call_rcu_data for child().
  *
@@ -2937,13 +2975,10 @@ child (__attribute__((unused)) void *param)
 	pthread_t check_thr, uevent_thr, uxlsnr_thr, uevq_thr, dmevent_thr;
 	pthread_attr_t log_attr, misc_attr, uevent_attr;
 	struct vectors * vecs;
-	struct multipath * mpp;
-	int i;
 	int rc;
 	int pid_fd = -1;
 	struct config *conf;
 	char *envp;
-	int queue_without_daemon;
 	enum daemon_status state;
 
 	mlockall(MCL_CURRENT | MCL_FUTURE);
@@ -3108,17 +3143,6 @@ child (__attribute__((unused)) void *param)
 	if (poll_dmevents)
 		pthread_cancel(dmevent_thr);
 
-	conf = get_multipath_config();
-	queue_without_daemon = conf->queue_without_daemon;
-	put_multipath_config(conf);
-
-	lock(&vecs->lock);
-	if (queue_without_daemon == QUE_NO_DAEMON_OFF)
-		vector_foreach_slot(vecs->mpvec, mpp, i)
-			dm_queue_if_no_path(mpp->alias, 0);
-	remove_maps_and_stop_waiters(vecs);
-	unlock(&vecs->lock);
-
 	pthread_join(check_thr, NULL);
 	pthread_join(uevent_thr, NULL);
 	pthread_join(uxlsnr_thr, NULL);
@@ -3128,15 +3152,7 @@ child (__attribute__((unused)) void *param)
 
 	stop_io_err_stat_thread();
 
-	lock(&vecs->lock);
-	free_pathvec(vecs->pathvec, FREE_PATHS);
-	vecs->pathvec = NULL;
-	unlock(&vecs->lock);
-
-	pthread_mutex_destroy(&vecs->lock.mutex);
-	FREE(vecs);
-	vecs = NULL;
-
+	cleanup_vecs();
 	cleanup_foreign();
 	cleanup_checkers();
 	cleanup_prio();
-- 
2.17.2