core: disable event sources before unreffing them

This mirrors the change done for systemd-resolved in
97935302283729c9206b84f5e00b1aff0f78ad19. Quoting that patch:

> We generally operate on the assumption that a source is "gone" as soon as we
> unref it. This is generally true because we have the only reference. But if
> something else holds the reference, our unref doesn't really stop the source
> and it could fire again.

In particular, we take temporary references from sd-event code, and when called
from an sd-event callback, we could temporarily see this elevated reference
count. This patch doesn't seem to change anything, but I think it's nicer to do
the same change as in other places and not rely on _unref() immediately
disabling the source.

1 files changed, 5 insertions, 5 deletions

diff --git a/src/core/swap.c b/src/core/swap.c
index a81b1928b8..a3b259abb6 100644
--- a/src/core/swap.c
+++ b/src/core/swap.c
@@ -179,7 +179,7 @@ static void swap_done(Unit *u) {
 
         swap_unwatch_control_pid(s);
 
-        s->timer_event_source = sd_event_source_unref(s->timer_event_source);
+        s->timer_event_source = sd_event_source_disable_unref(s->timer_event_source);
 }
 
 static int swap_arm_timer(Swap *s, usec_t usec) {
@@ -554,7 +554,7 @@ static void swap_set_state(Swap *s, SwapState state) {
         s->state = state;
 
         if (!SWAP_STATE_WITH_PROCESS(state)) {
-                s->timer_event_source = sd_event_source_unref(s->timer_event_source);
+                s->timer_event_source = sd_event_source_disable_unref(s->timer_event_source);
                 swap_unwatch_control_pid(s);
                 s->control_command = NULL;
                 s->control_command_id = _SWAP_EXEC_COMMAND_INVALID;
@@ -715,7 +715,7 @@ static int swap_spawn(Swap *s, ExecCommand *c, pid_t *_pid) {
         return 0;
 
 fail:
-        s->timer_event_source = sd_event_source_unref(s->timer_event_source);
+        s->timer_event_source = sd_event_source_disable_unref(s->timer_event_source);
 
         return r;
 }
@@ -1373,7 +1373,7 @@ static int swap_following_set(Unit *u, Set **_set) {
 static void swap_shutdown(Manager *m) {
         assert(m);
 
-        m->swap_event_source = sd_event_source_unref(m->swap_event_source);
+        m->swap_event_source = sd_event_source_disable_unref(m->swap_event_source);
         m->proc_swaps = safe_fclose(m->proc_swaps);
         m->swaps_by_devnode = hashmap_free(m->swaps_by_devnode);
 }
@@ -1577,7 +1577,7 @@ static int swap_clean(Unit *u, ExecCleanMask mask) {
 fail:
         log_unit_warning_errno(u, r, "Failed to initiate cleaning: %m");
         s->clean_result = SWAP_FAILURE_RESOURCES;
-        s->timer_event_source = sd_event_source_unref(s->timer_event_source);
+        s->timer_event_source = sd_event_source_disable_unref(s->timer_event_source);
         return r;
 }