From cb1a8f709ff3c27fc9f43aa27f985131422795bc Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>

Date: Tue, 13 Feb 2018 10:50:13 +0100

Subject: [PATCH] pid1: rename unit_check_gc to unit_may_gc

"check" is unclear: what is true, what is false? Let's rename to "can_gc" and

revert the return value ("positive" values are easier to grok).

v2:

- rename from unit_can_gc to unit_may_gc

(cherry picked from commit f2f725e5cc950e84ebfd09bd64bc01c0ebdb6734)

(cherry picked from commit 1716821fc5b93667a0bf821b25905de00818aec9)

Related: #1729228

---

 src/core/automount.c | 13 ++++++++-----

 src/core/manager.c   |  2 +-

 src/core/mount.c     |  9 ++++++---

 src/core/scope.c     |  8 ++++----

 src/core/service.c   |  8 ++++----

 src/core/socket.c    |  6 +++---

 src/core/socket.h    |  4 ++--

 src/core/swap.c      |  9 ++++++---

 src/core/unit.c      | 31 +++++++++++++++++--------------

 src/core/unit.h      |  9 ++++-----

 10 files changed, 55 insertions(+), 44 deletions(-)

diff --git a/src/core/automount.c b/src/core/automount.c

index 4678bdc7c9..7b9c4aaf1d 100644

--- a/src/core/automount.c

+++ b/src/core/automount.c

@@ -936,13 +936,16 @@ static const char *automount_sub_state_to_string(Unit *u) {

         return automount_state_to_string(AUTOMOUNT(u)->state);

 }

-static bool automount_check_gc(Unit *u) {

+static bool automount_may_gc(Unit *u) {

+        Unit *t;

+

         assert(u);

-        if (!UNIT_TRIGGER(u))

-                return false;

+        t = UNIT_TRIGGER(u);

+        if (!t)

+                return true;

-        return UNIT_VTABLE(UNIT_TRIGGER(u))->check_gc(UNIT_TRIGGER(u));

+        return UNIT_VTABLE(t)->may_gc(t);

 }

 static int automount_dispatch_io(sd_event_source *s, int fd, uint32_t events, void *userdata) {

@@ -1115,7 +1118,7 @@ const UnitVTable automount_vtable = {

         .active_state = automount_active_state,

         .sub_state_to_string = automount_sub_state_to_string,

-        .check_gc = automount_check_gc,

+        .may_gc = automount_may_gc,

         .reset_failed = automount_reset_failed,

diff --git a/src/core/manager.c b/src/core/manager.c

index 3bca61d0b1..9dfdd67860 100644

--- a/src/core/manager.c

+++ b/src/core/manager.c

@@ -871,7 +871,7 @@ static void unit_gc_sweep(Unit *u, unsigned gc_marker) {

         if (u->in_cleanup_queue)

                 goto bad;

-        if (unit_check_gc(u))

+        if (!unit_may_gc(u))

                 goto good;

         u->gc_marker = gc_marker + GC_OFFSET_IN_PATH;

diff --git a/src/core/mount.c b/src/core/mount.c

index c7aed2333f..8a25ebd163 100644

--- a/src/core/mount.c

+++ b/src/core/mount.c

@@ -1180,12 +1180,15 @@ _pure_ static const char *mount_sub_state_to_string(Unit *u) {

         return mount_state_to_string(MOUNT(u)->state);

 }

-_pure_ static bool mount_check_gc(Unit *u) {

+_pure_ static bool mount_may_gc(Unit *u) {

         Mount *m = MOUNT(u);

         assert(m);

-        return m->from_proc_self_mountinfo;

+        if (m->from_proc_self_mountinfo)

+                return false;

+

+        return true;

 }

 static void mount_sigchld_event(Unit *u, pid_t pid, int code, int status) {

@@ -1954,7 +1957,7 @@ const UnitVTable mount_vtable = {

         .active_state = mount_active_state,

         .sub_state_to_string = mount_sub_state_to_string,

-        .check_gc = mount_check_gc,

+        .may_gc = mount_may_gc,

         .sigchld_event = mount_sigchld_event,

diff --git a/src/core/scope.c b/src/core/scope.c

index 29954ba285..e9b45aa3f8 100644

--- a/src/core/scope.c

+++ b/src/core/scope.c

@@ -381,7 +381,7 @@ static int scope_deserialize_item(Unit *u, const char *key, const char *value, F

         return 0;

 }

-static bool scope_check_gc(Unit *u) {

+static bool scope_may_gc(Unit *u) {

         assert(u);

         /* Never clean up scopes that still have a process around,

@@ -392,10 +392,10 @@ static bool scope_check_gc(Unit *u) {

                 r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, true);

                 if (r <= 0)

-                        return true;

+                        return false;

         }

-        return false;

+        return true;

 }

 static void scope_notify_cgroup_empty_event(Unit *u) {

@@ -547,7 +547,7 @@ const UnitVTable scope_vtable = {

         .active_state = scope_active_state,

         .sub_state_to_string = scope_sub_state_to_string,

-        .check_gc = scope_check_gc,

+        .may_gc = scope_may_gc,

         .sigchld_event = scope_sigchld_event,

diff --git a/src/core/service.c b/src/core/service.c

index 957c6f37cc..69ec916f2d 100644

--- a/src/core/service.c

+++ b/src/core/service.c

@@ -2436,7 +2436,7 @@ static const char *service_sub_state_to_string(Unit *u) {

         return service_state_to_string(SERVICE(u)->state);

 }

-static bool service_check_gc(Unit *u) {

+static bool service_may_gc(Unit *u) {

         Service *s = SERVICE(u);

         assert(s);

@@ -2446,9 +2446,9 @@ static bool service_check_gc(Unit *u) {

         if (cgroup_good(s) > 0 ||

             main_pid_good(s) > 0 ||

             control_pid_good(s) > 0)

-                return true;

+                return false;

-        return false;

+        return true;

 }

 _pure_ static bool service_check_snapshot(Unit *u) {

@@ -3461,7 +3461,7 @@ const UnitVTable service_vtable = {

         .active_state = service_active_state,

         .sub_state_to_string = service_sub_state_to_string,

-        .check_gc = service_check_gc,

+        .may_gc = service_may_gc,

         .check_snapshot = service_check_snapshot,

         .sigchld_event = service_sigchld_event,

diff --git a/src/core/socket.c b/src/core/socket.c

index efefe7ce5d..3e4cdd467f 100644

--- a/src/core/socket.c

+++ b/src/core/socket.c

@@ -2269,12 +2269,12 @@ const char* socket_port_type_to_string(SocketPort *p) {

         }

 }

-_pure_ static bool socket_check_gc(Unit *u) {

+_pure_ static bool socket_may_gc(Unit *u) {

         Socket *s = SOCKET(u);

         assert(u);

-        return s->n_connections > 0;

+        return s->n_connections == 0;

 }

 static int socket_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) {

@@ -2713,7 +2713,7 @@ const UnitVTable socket_vtable = {

         .active_state = socket_active_state,

         .sub_state_to_string = socket_sub_state_to_string,

-        .check_gc = socket_check_gc,

+        .may_gc = socket_may_gc,

         .sigchld_event = socket_sigchld_event,

diff --git a/src/core/socket.h b/src/core/socket.h

index a2e08998c0..cc1428b3f7 100644

--- a/src/core/socket.h

+++ b/src/core/socket.h

@@ -114,8 +114,8 @@ struct Socket {

         ExecRuntime *exec_runtime;

         /* For Accept=no sockets refers to the one service we'll

-        activate. For Accept=yes sockets is either NULL, or filled

-        when the next service we spawn. */

+         * activate. For Accept=yes sockets is either NULL, or filled

+         * to refer to the next service we spawn. */

         UnitRef service;

         SocketState state, deserialized_state;

diff --git a/src/core/swap.c b/src/core/swap.c

index e71de4e657..1f69736aa3 100644

--- a/src/core/swap.c

+++ b/src/core/swap.c

@@ -949,12 +949,15 @@ _pure_ static const char *swap_sub_state_to_string(Unit *u) {

         return swap_state_to_string(SWAP(u)->state);

 }

-_pure_ static bool swap_check_gc(Unit *u) {

+_pure_ static bool swap_may_gc(Unit *u) {

         Swap *s = SWAP(u);

         assert(s);

-        return s->from_proc_swaps;

+        if (s->from_proc_swaps)

+                return false;

+

+        return true;

 }

 static void swap_sigchld_event(Unit *u, pid_t pid, int code, int status) {

@@ -1497,7 +1500,7 @@ const UnitVTable swap_vtable = {

         .active_state = swap_active_state,

         .sub_state_to_string = swap_sub_state_to_string,

-        .check_gc = swap_check_gc,

+        .may_gc = swap_may_gc,

         .sigchld_event = swap_sigchld_event,

diff --git a/src/core/unit.c b/src/core/unit.c

index b004aa8fcd..1b8ec9a20e 100644

--- a/src/core/unit.c

+++ b/src/core/unit.c

@@ -282,15 +282,19 @@ int unit_set_description(Unit *u, const char *description) {

         return 0;

 }

-bool unit_check_gc(Unit *u) {

+bool unit_may_gc(Unit *u) {

         UnitActiveState state;

         assert(u);

+        /* Checks whether the unit is ready to be unloaded for garbage collection.

+         * Returns true when the unit may be collected, and false if there's some

+         * reason to keep it loaded. */

+

         if (u->job)

-                return true;

+                return false;

         if (u->nop_job)

-                return true;

+                return false;

         state = unit_active_state(u);

@@ -303,22 +307,21 @@ bool unit_check_gc(Unit *u) {

         /* But we keep the unit object around for longer when it is

          * referenced or configured to not be gc'ed */

         if (state != UNIT_INACTIVE)

-                return true;

+                return false;

         if (UNIT_VTABLE(u)->no_gc)

-                return true;

+                return false;

         if (u->no_gc)

-                return true;

+                return false;

         if (u->refs)

-                return true;

+                return false;

-        if (UNIT_VTABLE(u)->check_gc)

-                if (UNIT_VTABLE(u)->check_gc(u))

-                        return true;

+        if (UNIT_VTABLE(u)->may_gc && !UNIT_VTABLE(u)->may_gc(u))

+                return false;

-        return false;

+        return true;

 }

 void unit_add_to_load_queue(Unit *u) {

@@ -348,7 +351,7 @@ void unit_add_to_gc_queue(Unit *u) {

         if (u->in_gc_queue || u->in_cleanup_queue)

                 return;

-        if (unit_check_gc(u))

+        if (!unit_may_gc(u))

                 return;

         LIST_PREPEND(gc_queue, u->manager->gc_queue, u);

@@ -888,7 +891,7 @@ void unit_dump(Unit *u, FILE *f, const char *prefix) {

                 "%s\tActive Enter Timestamp: %s\n"

                 "%s\tActive Exit Timestamp: %s\n"

                 "%s\tInactive Enter Timestamp: %s\n"

-                "%s\tGC Check Good: %s\n"

+                "%s\tMay GC: %s\n"

                 "%s\tNeed Daemon Reload: %s\n"

                 "%s\tTransient: %s\n"

                 "%s\tSlice: %s\n"

@@ -905,7 +908,7 @@ void unit_dump(Unit *u, FILE *f, const char *prefix) {

                 prefix, strna(format_timestamp(timestamp2, sizeof(timestamp2), u->active_enter_timestamp.realtime)),

                 prefix, strna(format_timestamp(timestamp3, sizeof(timestamp3), u->active_exit_timestamp.realtime)),

                 prefix, strna(format_timestamp(timestamp4, sizeof(timestamp4), u->inactive_enter_timestamp.realtime)),

-                prefix, yes_no(unit_check_gc(u)),

+                prefix, yes_no(unit_may_gc(u)),

                 prefix, yes_no(unit_need_daemon_reload(u)),

                 prefix, yes_no(u->transient),

                 prefix, strna(unit_slice_name(u)),

diff --git a/src/core/unit.h b/src/core/unit.h

index 091ef7596e..3f411a1793 100644

--- a/src/core/unit.h

+++ b/src/core/unit.h

@@ -353,10 +353,9 @@ struct UnitVTable {

          * unit is in. */

         const char* (*sub_state_to_string)(Unit *u);

-        /* Return true when there is reason to keep this entry around

-         * even nothing references it and it isn't active in any

-         * way */

-        bool (*check_gc)(Unit *u);

+        /* Return false when there is a reason to prevent this unit from being gc'ed

+         * even though nothing references it and it isn't active in any way. */

+        bool (*may_gc)(Unit *u);

         /* When the unit is not running and no job for it queued we

          * shall release its runtime resources */

@@ -496,7 +495,7 @@ int unit_add_exec_dependencies(Unit *u, ExecContext *c);

 int unit_choose_id(Unit *u, const char *name);

 int unit_set_description(Unit *u, const char *description);

-bool unit_check_gc(Unit *u);

+bool unit_may_gc(Unit *u);

 void unit_add_to_load_queue(Unit *u);

 void unit_add_to_dbus_queue(Unit *u);