From: Mike Yuan <me@yhndnzj.com>
Date: Tue, 16 Apr 2024 17:32:27 +0000 (+0800)
Subject: systemctl-start-unit: Subscribe() is unnecessary if we RefUnit explicitly
X-Git-Tag: v256-rc1~121^2~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ad6b84d9601f6009fb7deeaa82e0c0901e511b1e;p=thirdparty%2Fsystemd.git

systemctl-start-unit: Subscribe() is unnecessary if we RefUnit explicitly

Subscribe() enables full signal delivery on API bus. But aside from
that, if a unit/job is explicitly Ref()'d, manager also emits the
signal. See bus_foreach_bus() for details.

bus-wait-for-units refs every unit to wait for, so there's no need
to Subscribe() on top of that. In verb_clean_or_freeze() Subscribe()
is not called either.
---

diff --git a/src/systemctl/systemctl-start-unit.c b/src/systemctl/systemctl-start-unit.c
index c1574f019e2..8068d77d1cd 100644
--- a/src/systemctl/systemctl-start-unit.c
+++ b/src/systemctl/systemctl-start-unit.c
@@ -381,10 +381,6 @@ int verb_start(int argc, char *argv[], void *userdata) {
         }
 
         if (arg_wait) {
-                r = bus_call_method_async(bus, NULL, bus_systemd_mgr, "Subscribe", NULL, NULL, NULL);
-                if (r < 0)
-                        return log_error_errno(r, "Failed to enable subscription: %m");
-
                 r = bus_wait_for_units_new(bus, &wu);
                 if (r < 0)
                         return log_error_errno(r, "Failed to allocate unit watch context: %m");
@@ -408,7 +404,7 @@ int verb_start(int argc, char *argv[], void *userdata) {
                 }
 
         if (!arg_no_block) {
-                const char* extra_args[4];
+                const char *extra_args[4];
                 WaitJobsFlags flags = 0;
 
                 SET_FLAG(flags, BUS_WAIT_JOBS_LOG_ERROR, !arg_quiet);