core: simplify cg_[all_]unified()

cg_[all_]unified() test whether a specific controller or all controllers are on
the unified hierarchy.  While what's being asked is a simple binary question,
the callers must assume that the functions may fail any time, which
unnecessarily complicates their usages.  This complication is unnecessary.
Internally, the test result is cached anyway and there are only a few places
where the test actually needs to be performed.

This patch simplifies cg_[all_]unified().

* cg_[all_]unified() are updated to return bool.  If the result can't be
  decided, assertion failure is triggered.  Error handlings from their callers
  are dropped.

* cg_unified_flush() is updated to calculate the new result synchrnously and
  return whether it succeeded or not.  Places which need to flush the test
  result are updated to test for failure.  This ensures that all the following
  cg_[all_]unified() tests succeed.

* Places which expected possible cg_[all_]unified() failures are updated to
  call and test cg_unified_flush() before calling cg_[all_]unified().  This
  includes functions used while setting up mounts during boot and
  manager_setup_cgroup().

diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
index 6948ed393132cc701a3bb35ce58d08e1fd9a46b6..48623fb2350127deff3214d4a907467406aa627f 100644 (file)
--- a/src/basic/cgroup-util.c
+++ b/src/basic/cgroup-util.c
@@ -594,7 +594,7 @@ static int join_path_unified(const char *path, const char *suffix, char **fs) {
 }
 
 int cg_get_path(const char *controller, const char *path, const char *suffix, char **fs) {
-        int unified, r;
+        int r;
 
         assert(fs);
 
@@ -623,11 +623,7 @@ int cg_get_path(const char *controller, const char *path, const char *suffix, ch
         if (!cg_controller_is_valid(controller))
                 return -EINVAL;
 
-        unified = cg_all_unified();
-        if (unified < 0)
-                return unified;
-
-        if (unified > 0)
+        if (cg_all_unified())
                 r = join_path_unified(path, suffix, fs);
         else
                 r = join_path_legacy(controller, path, suffix, fs);
@@ -639,7 +635,6 @@ int cg_get_path(const char *controller, const char *path, const char *suffix, ch
 }
 
 static int controller_is_accessible(const char *controller) {
-        int unified;
 
         assert(controller);
 
@@ -651,10 +646,7 @@ static int controller_is_accessible(const char *controller) {
         if (!cg_controller_is_valid(controller))
                 return -EINVAL;
 
-        unified = cg_all_unified();
-        if (unified < 0)
-                return unified;
-        if (unified > 0) {
+        if (cg_all_unified()) {
                 /* We don't support named hierarchies if we are using
                  * the unified hierarchy. */
 
@@ -851,7 +843,7 @@ int cg_set_task_access(
                 gid_t gid) {
 
         _cleanup_free_ char *fs = NULL, *procs = NULL;
-        int r, unified;
+        int r;
 
         assert(path);
 
@@ -869,10 +861,7 @@ int cg_set_task_access(
         if (r < 0)
                 return r;
 
-        unified = cg_unified(controller);
-        if (unified < 0)
-                return unified;
-        if (unified)
+        if (cg_unified(controller))
                 return 0;
 
         /* Compatibility, Always keep values for "tasks" in sync with
@@ -925,7 +914,7 @@ int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
         char line[LINE_MAX];
         const char *fs;
         size_t cs = 0;
-        int unified;
+        bool unified;
 
         assert(path);
         assert(pid >= 0);
@@ -937,9 +926,7 @@ int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
                 controller = SYSTEMD_CGROUP_CONTROLLER;
 
         unified = cg_unified(controller);
-        if (unified < 0)
-                return unified;
-        if (unified == 0)
+        if (!unified)
                 cs = strlen(controller);
 
         fs = procfs_file_alloca(pid, "cgroup");
@@ -1001,14 +988,11 @@ int cg_pid_get_path(const char *controller, pid_t pid, char **path) {
 int cg_install_release_agent(const char *controller, const char *agent) {
         _cleanup_free_ char *fs = NULL, *contents = NULL;
         const char *sc;
-        int r, unified;
+        int r;
 
         assert(agent);
 
-        unified = cg_unified(controller);
-        if (unified < 0)
-                return unified;
-        if (unified) /* doesn't apply to unified hierarchy */
+        if (cg_unified(controller)) /* doesn't apply to unified hierarchy */
                 return -EOPNOTSUPP;
 
         r = cg_get_path(controller, NULL, "release_agent", &fs);
@@ -1054,12 +1038,9 @@ int cg_install_release_agent(const char *controller, const char *agent) {
 
 int cg_uninstall_release_agent(const char *controller) {
         _cleanup_free_ char *fs = NULL;
-        int r, unified;
+        int r;
 
-        unified = cg_unified(controller);
-        if (unified < 0)
-                return unified;
-        if (unified) /* Doesn't apply to unified hierarchy */
+        if (cg_unified(controller)) /* Doesn't apply to unified hierarchy */
                 return -EOPNOTSUPP;
 
         r = cg_get_path(controller, NULL, "notify_on_release", &fs);
@@ -1104,7 +1085,7 @@ int cg_is_empty(const char *controller, const char *path) {
 }
 
 int cg_is_empty_recursive(const char *controller, const char *path) {
-        int unified, r;
+        int r;
 
         assert(path);
 
@@ -1112,11 +1093,7 @@ int cg_is_empty_recursive(const char *controller, const char *path) {
         if (controller && (isempty(path) || path_equal(path, "/")))
                 return false;
 
-        unified = cg_unified(controller);
-        if (unified < 0)
-                return unified;
-
-        if (unified > 0) {
+        if (cg_unified(controller)) {
                 _cleanup_free_ char *t = NULL;
 
                 /* On the unified hierarchy we can check empty state
@@ -1986,7 +1963,7 @@ int cg_get_keyed_attribute(const char *controller, const char *path, const char
 
 int cg_create_everywhere(CGroupMask supported, CGroupMask mask, const char *path) {
         CGroupController c;
-        int r, unified;
+        int r;
 
         /* This one will create a cgroup in our private tree, but also
          * duplicate it in the trees specified in mask, and remove it
@@ -1998,10 +1975,7 @@ int cg_create_everywhere(CGroupMask supported, CGroupMask mask, const char *path
                 return r;
 
         /* If we are in the unified hierarchy, we are done now */
-        unified = cg_all_unified();
-        if (unified < 0)
-                return unified;
-        if (unified > 0)
+        if (cg_all_unified())
                 return 0;
 
         /* Otherwise, do the same in the other hierarchies */
@@ -2022,16 +1996,13 @@ int cg_create_everywhere(CGroupMask supported, CGroupMask mask, const char *path
 
 int cg_attach_everywhere(CGroupMask supported, const char *path, pid_t pid, cg_migrate_callback_t path_callback, void *userdata) {
         CGroupController c;
-        int r, unified;
+        int r;
 
         r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, path, pid);
         if (r < 0)
                 return r;
 
-        unified = cg_all_unified();
-        if (unified < 0)
-                return unified;
-        if (unified > 0)
+        if (cg_all_unified())
                 return 0;
 
         for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
@@ -2072,7 +2043,7 @@ int cg_attach_many_everywhere(CGroupMask supported, const char *path, Set* pids,
 
 int cg_migrate_everywhere(CGroupMask supported, const char *from, const char *to, cg_migrate_callback_t to_callback, void *userdata) {
         CGroupController c;
-        int r = 0, unified;
+        int r = 0;
 
         if (!path_equal(from, to))  {
                 r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, from, SYSTEMD_CGROUP_CONTROLLER, to, CGROUP_REMOVE);
@@ -2080,10 +2051,7 @@ int cg_migrate_everywhere(CGroupMask supported, const char *from, const char *to
                         return r;
         }
 
-        unified = cg_all_unified();
-        if (unified < 0)
-                return unified;
-        if (unified > 0)
+        if (cg_all_unified())
                 return r;
 
         for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
@@ -2107,16 +2075,13 @@ int cg_migrate_everywhere(CGroupMask supported, const char *from, const char *to
 
 int cg_trim_everywhere(CGroupMask supported, const char *path, bool delete_root) {
         CGroupController c;
-        int r, unified;
+        int r;
 
         r = cg_trim(SYSTEMD_CGROUP_CONTROLLER, path, delete_root);
         if (r < 0)
                 return r;
 
-        unified = cg_all_unified();
-        if (unified < 0)
-                return unified;
-        if (unified > 0)
+        if (cg_all_unified())
                 return r;
 
         for (c = 0; c < _CGROUP_CONTROLLER_MAX; c++) {
@@ -2133,16 +2098,13 @@ int cg_trim_everywhere(CGroupMask supported, const char *path, bool delete_root)
 
 int cg_mask_supported(CGroupMask *ret) {
         CGroupMask mask = 0;
-        int r, unified;
+        int r;
 
         /* Determines the mask of supported cgroup controllers. Only
          * includes controllers we can make sense of and that are
          * actually accessible. */
 
-        unified = cg_all_unified();
-        if (unified < 0)
-                return unified;
-        if (unified > 0) {
+        if (cg_all_unified()) {
                 _cleanup_free_ char *root = NULL, *controllers = NULL, *path = NULL;
                 const char *c;
 
@@ -2291,13 +2253,9 @@ static int cg_update_unified(void) {
         return 0;
 }
 
-int cg_unified(const char *controller) {
-
-        int r;
+bool cg_unified(const char *controller) {
 
-        r = cg_update_unified();
-        if (r < 0)
-                return r;
+        assert(cg_update_unified() >= 0);
 
         if (streq_ptr(controller, SYSTEMD_CGROUP_CONTROLLER))
                 return unified_cache >= CGROUP_UNIFIED_SYSTEMD;
@@ -2305,29 +2263,28 @@ int cg_unified(const char *controller) {
                 return unified_cache >= CGROUP_UNIFIED_ALL;
 }
 
-int cg_all_unified(void) {
+bool cg_all_unified(void) {
 
         return cg_unified(NULL);
 }
 
-void cg_unified_flush(void) {
+int cg_unified_flush(void) {
         unified_cache = CGROUP_UNIFIED_UNKNOWN;
+
+        return cg_update_unified();
 }
 
 int cg_enable_everywhere(CGroupMask supported, CGroupMask mask, const char *p) {
         _cleanup_free_ char *fs = NULL;
         CGroupController c;
-        int r, unified;
+        int r;
 
         assert(p);
 
         if (supported == 0)
                 return 0;
 
-        unified = cg_all_unified();
-        if (unified < 0)
-                return unified;
-        if (!unified) /* on the legacy hiearchy there's no joining of controllers defined */
+        if (!cg_all_unified()) /* on the legacy hiearchy there's no joining of controllers defined */
                 return 0;
 
         r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, p, "cgroup.subtree_control", &fs);
@@ -2359,14 +2316,13 @@ int cg_enable_everywhere(CGroupMask supported, CGroupMask mask, const char *p) {
 
 bool cg_is_unified_wanted(void) {
         static thread_local int wanted = -1;
-        int r, unified;
+        int r;
         bool b;
 
         /* If the hierarchy is already mounted, then follow whatever
          * was chosen for it. */
-        unified = cg_all_unified();
-        if (unified >= 0)
-                return unified;
+        if (cg_unified_flush() >= 0)
+                return cg_all_unified();
 
         /* Otherwise, let's see what the kernel command line has to
          * say. Since checking that is expensive, let's cache the
@@ -2387,7 +2343,7 @@ bool cg_is_legacy_wanted(void) {
 
 bool cg_is_unified_systemd_controller_wanted(void) {
         static thread_local int wanted = -1;
-        int r, unified;
+        int r;
         bool b;
 
         /* If the unified hierarchy is requested in full, no need to
@@ -2397,9 +2353,8 @@ bool cg_is_unified_systemd_controller_wanted(void) {
 
         /* If the hierarchy is already mounted, then follow whatever
          * was chosen for it. */
-        unified = cg_unified(SYSTEMD_CGROUP_CONTROLLER);
-        if (unified >= 0)
-                return unified;
+        if (cg_unified_flush() >= 0)
+                return cg_unified(SYSTEMD_CGROUP_CONTROLLER);
 
         /* Otherwise, let's see what the kernel command line has to
          * say. Since checking that is expensive, let's cache the

diff --git a/src/basic/cgroup-util.h b/src/basic/cgroup-util.h
index 0aa27c4cd7cf181a095626389f8157b0156f455a..09dcc2b38e2f0f5d287add03c6d93319814b187e 100644 (file)
--- a/src/basic/cgroup-util.h
+++ b/src/basic/cgroup-util.h
@@ -240,9 +240,9 @@ int cg_kernel_controllers(Set *controllers);
 
 bool cg_ns_supported(void);
 
-int cg_all_unified(void);
-int cg_unified(const char *controller);
-void cg_unified_flush(void);
+bool cg_all_unified(void);
+bool cg_unified(const char *controller);
+int cg_unified_flush(void);
 
 bool cg_is_unified_wanted(void);
 bool cg_is_legacy_wanted(void);

diff --git a/src/cgls/cgls.c b/src/cgls/cgls.c
index 5574c145553edc3f005837b88db971e13d3ef885..40db82f9ae4d02be77adb1bd279e464d7dad0719 100644 (file)
--- a/src/cgls/cgls.c
+++ b/src/cgls/cgls.c
@@ -158,7 +158,7 @@ static int parse_argv(int argc, char *argv[]) {
 
 static void show_cg_info(const char *controller, const char *path) {
 
-        if (cg_all_unified() <= 0 && controller && !streq(controller, SYSTEMD_CGROUP_CONTROLLER))
+        if (!cg_all_unified() && controller && !streq(controller, SYSTEMD_CGROUP_CONTROLLER))
                 printf("Controller %s; ", controller);
 
         printf("Control group %s:\n", isempty(path) ? "/" : path);

diff --git a/src/cgtop/cgtop.c b/src/cgtop/cgtop.c
index 50ac6a58b0aa2870299493aa59ec30b612d3dd38..45c050c9c3a54600cbcc0af3e081abf301d2b590 100644 (file)
--- a/src/cgtop/cgtop.c
+++ b/src/cgtop/cgtop.c
@@ -214,7 +214,7 @@ static int process(
                 uint64_t new_usage;
                 nsec_t timestamp;
 
-                if (cg_all_unified() > 0) {
+                if (cg_all_unified()) {
                         const char *keys[] = { "usage_usec", NULL };
                         _cleanup_free_ char *val = NULL;
 
@@ -274,7 +274,7 @@ static int process(
         } else if (streq(controller, "memory")) {
                 _cleanup_free_ char *p = NULL, *v = NULL;
 
-                if (cg_all_unified() <= 0)
+                if (!cg_all_unified())
                         r = cg_get_path(controller, path, "memory.usage_in_bytes", &p);
                 else
                         r = cg_get_path(controller, path, "memory.current", &p);
@@ -294,15 +294,14 @@ static int process(
                 if (g->memory > 0)
                         g->memory_valid = true;
 
-        } else if ((streq(controller, "io") && cg_all_unified() > 0) ||
-                   (streq(controller, "blkio") && cg_all_unified() <= 0)) {
+        } else if ((streq(controller, "io") && cg_all_unified()) ||
+                   (streq(controller, "blkio") && !cg_all_unified())) {
                 _cleanup_fclose_ FILE *f = NULL;
                 _cleanup_free_ char *p = NULL;
-                bool unified = cg_all_unified() > 0;
                 uint64_t wr = 0, rd = 0;
                 nsec_t timestamp;
 
-                r = cg_get_path(controller, path, unified ? "io.stat" : "blkio.io_service_bytes", &p);
+                r = cg_get_path(controller, path, cg_all_unified() ? "io.stat" : "blkio.io_service_bytes", &p);
                 if (r < 0)
                         return r;
 
@@ -325,7 +324,7 @@ static int process(
                         l += strcspn(l, WHITESPACE);
                         l += strspn(l, WHITESPACE);
 
-                        if (unified) {
+                        if (cg_all_unified()) {
                                 while (!isempty(l)) {
                                         if (sscanf(l, "rbytes=%" SCNu64, &k))
                                                 rd += k;

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 5789e2aa82536be66f10d30bb7112b39884ae917..17e0857729245d2a4374ffcbb404c4b79213736f 100644 (file)
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -678,7 +678,7 @@ static void cgroup_context_apply(Unit *u, CGroupMask mask, ManagerState state) {
                 bool has_weight = cgroup_context_has_cpu_weight(c);
                 bool has_shares = cgroup_context_has_cpu_shares(c);
 
-                if (cg_all_unified() > 0) {
+                if (cg_all_unified()) {
                         uint64_t weight;
 
                         if (has_weight)
@@ -858,7 +858,7 @@ static void cgroup_context_apply(Unit *u, CGroupMask mask, ManagerState state) {
         }
 
         if ((mask & CGROUP_MASK_MEMORY) && !is_root) {
-                if (cg_all_unified() > 0) {
+                if (cg_all_unified()) {
                         uint64_t max;
                         uint64_t swap_max = CGROUP_LIMIT_MAX;
 
@@ -1033,7 +1033,7 @@ CGroupMask unit_get_own_mask(Unit *u) {
                 e = unit_get_exec_context(u);
                 if (!e ||
                     exec_context_maintains_privileges(e) ||
-                    cg_all_unified() > 0)
+                    cg_all_unified())
                         return _CGROUP_MASK_ALL;
         }
 
@@ -1260,10 +1260,7 @@ int unit_watch_cgroup(Unit *u) {
                 return 0;
 
         /* Only applies to the unified hierarchy */
-        r = cg_unified(SYSTEMD_CGROUP_CONTROLLER);
-        if (r < 0)
-                return log_unit_error_errno(u, r, "Failed detect whether the unified hierarchy is used: %m");
-        if (r == 0)
+        if (!cg_unified(SYSTEMD_CGROUP_CONTROLLER))
                 return 0;
 
         /* Don't watch the root slice, it's pointless. */
@@ -1683,7 +1680,7 @@ int unit_watch_all_pids(Unit *u) {
         if (!u->cgroup_path)
                 return -ENOENT;
 
-        if (cg_unified(SYSTEMD_CGROUP_CONTROLLER) > 0) /* On unified we can use proper notifications */
+        if (cg_unified(SYSTEMD_CGROUP_CONTROLLER)) /* On unified we can use proper notifications */
                 return 0;
 
         return unit_watch_pids_in_path(u, u->cgroup_path);
@@ -1756,7 +1753,7 @@ static int on_cgroup_inotify_event(sd_event_source *s, int fd, uint32_t revents,
 int manager_setup_cgroup(Manager *m) {
         _cleanup_free_ char *path = NULL;
         CGroupController c;
-        int r, all_unified, systemd_unified;
+        int r;
         char *e;
 
         assert(m);
@@ -1793,16 +1790,13 @@ int manager_setup_cgroup(Manager *m) {
         if (r < 0)
                 return log_error_errno(r, "Cannot find cgroup mount point: %m");
 
-        all_unified = cg_all_unified();
-        systemd_unified = cg_unified(SYSTEMD_CGROUP_CONTROLLER);
-
-        if (all_unified < 0 || systemd_unified < 0)
-                return log_error_errno(all_unified < 0 ? all_unified : systemd_unified,
-                                       "Couldn't determine if we are running in the unified hierarchy: %m");
+        r = cg_unified_flush();
+        if (r < 0)
+                return log_error_errno(r, "Couldn't determine if we are running in the unified hierarchy: %m");
 
-        if (all_unified > 0)
+        if (cg_all_unified())
                 log_debug("Unified cgroup hierarchy is located at %s.", path);
-        else if (systemd_unified > 0)
+        else if (cg_unified(SYSTEMD_CGROUP_CONTROLLER))
                 log_debug("Unified cgroup hierarchy is located at %s. Controllers are on legacy hierarchies.", path);
         else
                 log_debug("Using cgroup controller " SYSTEMD_CGROUP_CONTROLLER ". File system hierarchy is at %s.", path);
@@ -1811,7 +1805,7 @@ int manager_setup_cgroup(Manager *m) {
                 const char *scope_path;
 
                 /* 3. Install agent */
-                if (systemd_unified) {
+                if (cg_unified(SYSTEMD_CGROUP_CONTROLLER)) {
 
                         /* In the unified hierarchy we can get
                          * cgroup empty notifications via inotify. */
@@ -1871,7 +1865,7 @@ int manager_setup_cgroup(Manager *m) {
                         return log_error_errno(errno, "Failed to open pin file: %m");
 
                 /* 6.  Always enable hierarchical support if it exists... */
-                if (!all_unified)
+                if (!cg_all_unified())
                         (void) cg_set_attribute("memory", "/", "memory.use_hierarchy", "1");
         }
 
@@ -1997,7 +1991,7 @@ int unit_get_memory_current(Unit *u, uint64_t *ret) {
         if ((u->cgroup_realized_mask & CGROUP_MASK_MEMORY) == 0)
                 return -ENODATA;
 
-        if (cg_all_unified() <= 0)
+        if (!cg_all_unified())
                 r = cg_get_attribute("memory", u->cgroup_path, "memory.usage_in_bytes", &v);
         else
                 r = cg_get_attribute("memory", u->cgroup_path, "memory.current", &v);
@@ -2042,7 +2036,7 @@ static int unit_get_cpu_usage_raw(Unit *u, nsec_t *ret) {
         if (!u->cgroup_path)
                 return -ENODATA;
 
-        if (cg_all_unified() > 0) {
+        if (cg_all_unified()) {
                 const char *keys[] = { "usage_usec", NULL };
                 _cleanup_free_ char *val = NULL;
                 uint64_t us;

diff --git a/src/core/manager.c b/src/core/manager.c
index b509adfc648cf2399916487c32cd93368bcacc04..b2cd352a0cce6c61760f0b12cb9ccc8781187ae0 100644 (file)
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -775,7 +775,7 @@ static int manager_setup_cgroups_agent(Manager *m) {
         if (!MANAGER_IS_SYSTEM(m))
                 return 0;
 
-        if (cg_unified(SYSTEMD_CGROUP_CONTROLLER) > 0) /* We don't need this anymore on the unified hierarchy */
+        if (cg_unified(SYSTEMD_CGROUP_CONTROLLER)) /* We don't need this anymore on the unified hierarchy */
                 return 0;
 
         if (m->cgroups_agent_fd < 0) {

diff --git a/src/core/scope.c b/src/core/scope.c
index 9540fb67d98f44b5c5be1fc8ae5800e31cd704e5..5e068a76d1c3fc09d06e83a1aa8add60cee65829 100644 (file)
--- a/src/core/scope.c
+++ b/src/core/scope.c
@@ -475,7 +475,7 @@ static void scope_sigchld_event(Unit *u, pid_t pid, int code, int status) {
 
         /* If the PID set is empty now, then let's finish this off
            (On unified we use proper notifications) */
-        if (cg_unified(SYSTEMD_CGROUP_CONTROLLER) <= 0 && set_isempty(u->pids))
+        if (!cg_unified(SYSTEMD_CGROUP_CONTROLLER) && set_isempty(u->pids))
                 scope_notify_cgroup_empty_event(u);
 }
 

diff --git a/src/core/service.c b/src/core/service.c
index 54074ff7bcc6da5bc4f79d5023f5299accd9d014..0c2eb18f381dab4e475188652111763ef877729b 100644 (file)
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -2938,7 +2938,7 @@ static void service_sigchld_event(Unit *u, pid_t pid, int code, int status) {
 
         /* If the PID set is empty now, then let's finish this off
            (On unified we use proper notifications) */
-        if (cg_unified(SYSTEMD_CGROUP_CONTROLLER) <= 0 && set_isempty(u->pids))
+        if (!cg_unified(SYSTEMD_CGROUP_CONTROLLER) && set_isempty(u->pids))
                 service_notify_cgroup_empty_event(u);
 }
 

diff --git a/src/core/unit.c b/src/core/unit.c
index bb05d2abfbd602a2977ff6d683279397adb17626..685df6f00de6ac63da59a71d62a0ec15f350d283 100644 (file)
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -3897,8 +3897,8 @@ int unit_kill_context(
                          * there we get proper events. Hence rely on
                          * them.*/
 
-                        if  (cg_unified(SYSTEMD_CGROUP_CONTROLLER) > 0 ||
-                             (detect_container() == 0 && !unit_cgroup_delegate(u)))
+                        if (cg_unified(SYSTEMD_CGROUP_CONTROLLER) ||
+                            (detect_container() == 0 && !unit_cgroup_delegate(u)))
                                 wait_for_exit = true;
 
                         if (send_sighup) {

diff --git a/src/libsystemd/sd-bus/test-bus-creds.c b/src/libsystemd/sd-bus/test-bus-creds.c
index 6fdcfa41287d4dd5df3ab62c29ebd407741edaa9..64bd76a576ee7e1ba36492a4e744a29b6156d080 100644 (file)
--- a/src/libsystemd/sd-bus/test-bus-creds.c
+++ b/src/libsystemd/sd-bus/test-bus-creds.c
@@ -31,7 +31,7 @@ int main(int argc, char *argv[]) {
         log_parse_environment();
         log_open();
 
-        if (cg_all_unified() == -ENOMEDIUM) {
+        if (cg_unified_flush() == -ENOMEDIUM) {
                 log_info("Skipping test: /sys/fs/cgroup/ not available");
                 return EXIT_TEST_SKIP;
         }

diff --git a/src/nspawn/nspawn-cgroup.c b/src/nspawn/nspawn-cgroup.c
index 5274767b96bf5733f74a6b2153ca5d75287842b9..4678a7e349c848ddd38bcfae8e1bf9ee2c0c1665 100644 (file)
--- a/src/nspawn/nspawn-cgroup.c
+++ b/src/nspawn/nspawn-cgroup.c
@@ -78,13 +78,9 @@ int sync_cgroup(pid_t pid, CGroupUnified unified_requested, uid_t arg_uid_shift)
         char tree[] = "/tmp/unifiedXXXXXX", pid_string[DECIMAL_STR_MAX(pid) + 1];
         bool undo_mount = false;
         const char *fn;
-        int unified, r;
-
-        unified = cg_unified(SYSTEMD_CGROUP_CONTROLLER);
-        if (unified < 0)
-                return log_error_errno(unified, "Failed to determine whether the unified hierarchy is used: %m");
+        int r;
 
-        if ((unified > 0) == (unified_requested >= CGROUP_UNIFIED_SYSTEMD))
+        if (cg_unified(SYSTEMD_CGROUP_CONTROLLER) == (unified_requested >= CGROUP_UNIFIED_SYSTEMD))
                 return 0;
 
         /* When the host uses the legacy cgroup setup, but the
@@ -100,7 +96,7 @@ int sync_cgroup(pid_t pid, CGroupUnified unified_requested, uid_t arg_uid_shift)
         if (!mkdtemp(tree))
                 return log_error_errno(errno, "Failed to generate temporary mount point for unified hierarchy: %m");
 
-        if (unified)
+        if (cg_unified(SYSTEMD_CGROUP_CONTROLLER))
                 r = mount_verbose(LOG_ERR, "cgroup", tree, "cgroup",
                                   MS_NOSUID|MS_NOEXEC|MS_NODEV, "none,name=systemd,xattr");
         else
@@ -142,7 +138,7 @@ finish:
 int create_subcgroup(pid_t pid, CGroupUnified unified_requested) {
         _cleanup_free_ char *cgroup = NULL;
         const char *child;
-        int unified, r;
+        int r;
         CGroupMask supported;
 
         /* In the unified hierarchy inner nodes may only contain
@@ -154,10 +150,7 @@ int create_subcgroup(pid_t pid, CGroupUnified unified_requested) {
         if (unified_requested == CGROUP_UNIFIED_NONE)
                 return 0;
 
-        unified = cg_unified(SYSTEMD_CGROUP_CONTROLLER);
-        if (unified < 0)
-                return log_error_errno(unified, "Failed to determine whether the unified hierarchy is used: %m");
-        if (unified == 0)
+        if (!cg_unified(SYSTEMD_CGROUP_CONTROLLER))
                 return 0;
 
         r = cg_mask_supported(&supported);

diff --git a/src/nspawn/nspawn-mount.c b/src/nspawn/nspawn-mount.c
index 4b2838b752c3f906c8bc9d1294379bdf331de1c1..1493ef6aad542b208bfd90746f87bff6049ad025 100644 (file)
--- a/src/nspawn/nspawn-mount.c
+++ b/src/nspawn/nspawn-mount.c
@@ -994,7 +994,7 @@ static int mount_legacy_cgns_supported(
                         return r;
         }
 
-        if (cg_all_unified() > 0)
+        if (cg_all_unified())
                 goto skip_controllers;
 
         controllers = set_new(&string_hash_ops);
@@ -1091,7 +1091,7 @@ static int mount_legacy_cgns_unsupported(
                         return r;
         }
 
-        if (cg_all_unified() > 0)
+        if (cg_all_unified())
                 goto skip_controllers;
 
         controllers = set_new(&string_hash_ops);

diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index f5956bcb15abd7cdd0c370a4d45f8edc24b456b1..75b6728688a71e2a83a013e82739c907e6a71bf1 100644 (file)
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -316,7 +316,7 @@ static int custom_mount_check_all(void) {
 
 static int detect_unified_cgroup_hierarchy(const char *directory) {
         const char *e;
-        int r, all_unified, systemd_unified;
+        int r;
 
         /* Allow the user to control whether the unified hierarchy is used */
         e = getenv("UNIFIED_CGROUP_HIERARCHY");
@@ -332,15 +332,8 @@ static int detect_unified_cgroup_hierarchy(const char *directory) {
                 return 0;
         }
 
-        all_unified = cg_all_unified();
-        systemd_unified = cg_unified(SYSTEMD_CGROUP_CONTROLLER);
-
-        if (all_unified < 0 || systemd_unified < 0)
-                return log_error_errno(all_unified < 0 ? all_unified : systemd_unified,
-                                       "Failed to determine whether the unified cgroups hierarchy is used: %m");
-
         /* Otherwise inherit the default from the host system */
-        if (all_unified > 0) {
+        if (cg_all_unified()) {
                 /* Unified cgroup hierarchy support was added in 230. Unfortunately the detection
                  * routine only detects 231, so we'll have a false negative here for 230. */
                 r = systemd_installation_has_version(directory, 230);
@@ -350,7 +343,7 @@ static int detect_unified_cgroup_hierarchy(const char *directory) {
                         arg_unified_cgroup_hierarchy = CGROUP_UNIFIED_ALL;
                 else
                         arg_unified_cgroup_hierarchy = CGROUP_UNIFIED_NONE;
-        } else if (systemd_unified > 0) {
+        } else if (cg_unified(SYSTEMD_CGROUP_CONTROLLER)) {
                 /* Mixed cgroup hierarchy support was added in 232 */
                 r = systemd_installation_has_version(directory, 232);
                 if (r < 0)
@@ -3533,7 +3526,10 @@ int main(int argc, char *argv[]) {
 
         log_parse_environment();
         log_open();
-        cg_unified_flush();
+
+        r = cg_unified_flush();
+        if (r < 0)
+                return log_error_errno(r, "Failed to determine whether the unified cgroups hierarchy is used: %m");
 
         /* Make sure rename_process() in the stub init process can work */
         saved_argv = argv;