freezer: remove unused @sig_only from freeze_task()

After "freezer: make freezing() test freeze conditions in effect
instead of TIF_FREEZE", freezing() returns authoritative answer on
whether the current task should freeze or not and freeze_task()
doesn't need or use @sig_only.  Remove it.

While at it, rewrite function comment for freeze_task() and rename
@sig_only to @user_only in try_to_freeze_tasks().

This patch doesn't cause any functional change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>

include/linux/freezer.h

@@ -48,7 +48,7 @@ static inline bool try_to_freeze(void)
 	return __refrigerator(false);
 }
 
-extern bool freeze_task(struct task_struct *p, bool sig_only);
+extern bool freeze_task(struct task_struct *p);
 extern bool __set_freezable(bool with_signal);
 
 #ifdef CONFIG_CGROUP_FREEZER

kernel/cgroup_freezer.c

@@ -206,7 +206,7 @@ static void freezer_fork(struct cgroup_subsys *ss, struct task_struct *task)
 
 	/* Locking avoids race with FREEZING -> THAWED transitions. */
 	if (freezer->state == CGROUP_FREEZING)
-		freeze_task(task, true);
+		freeze_task(task);
 	spin_unlock_irq(&freezer->lock);
 }
 
@@ -274,7 +274,7 @@ static int try_to_freeze_cgroup(struct cgroup *cgroup, struct freezer *freezer)
 
 	cgroup_iter_start(cgroup, &it);
 	while ((task = cgroup_iter_next(cgroup, &it))) {
-		if (!freeze_task(task, true))
+		if (!freeze_task(task))
 			continue;
 		if (frozen(task))
 			continue;

kernel/freezer.c

@@ -100,20 +100,17 @@ static void fake_signal_wake_up(struct task_struct *p)
 }
 
 /**
- *	freeze_task - send a freeze request to given task
- *	@p: task to send the request to
- *	@sig_only: if set, the request will only be sent if the task has the
- *		PF_FREEZER_NOSIG flag unset
- *	Return value: 'false', if @sig_only is set and the task has
- *		PF_FREEZER_NOSIG set or the task is frozen, 'true', otherwise
+ * freeze_task - send a freeze request to given task
+ * @p: task to send the request to
  *
- *	The freeze request is sent by setting the tasks's TIF_FREEZE flag and
- *	either sending a fake signal to it or waking it up, depending on whether
- *	or not it has PF_FREEZER_NOSIG set.  If @sig_only is set and the task
- *	has PF_FREEZER_NOSIG set (ie. it is a typical kernel thread), its
- *	TIF_FREEZE flag will not be set.
+ * If @p is freezing, the freeze request is sent by setting %TIF_FREEZE
+ * flag and either sending a fake signal to it or waking it up, depending
+ * on whether it has %PF_FREEZER_NOSIG set.
+ *
+ * RETURNS:
+ * %false, if @p is not freezing or already frozen; %true, otherwise
  */
-bool freeze_task(struct task_struct *p, bool sig_only)
+bool freeze_task(struct task_struct *p)
 {
 	unsigned long flags;
 

kernel/power/process.c

@@ -22,7 +22,7 @@
  */
 #define TIMEOUT	(20 * HZ)
 
-static int try_to_freeze_tasks(bool sig_only)
+static int try_to_freeze_tasks(bool user_only)
 {
 	struct task_struct *g, *p;
 	unsigned long end_time;
@@ -37,14 +37,14 @@ static int try_to_freeze_tasks(bool sig_only)
 
 	end_time = jiffies + TIMEOUT;
 
-	if (!sig_only)
+	if (!user_only)
 		freeze_workqueues_begin();
 
 	while (true) {
 		todo = 0;
 		read_lock(&tasklist_lock);
 		do_each_thread(g, p) {
-			if (p == current || !freeze_task(p, sig_only))
+			if (p == current || !freeze_task(p))
 				continue;
 
 			/*
@@ -65,7 +65,7 @@ static int try_to_freeze_tasks(bool sig_only)
 		} while_each_thread(g, p);
 		read_unlock(&tasklist_lock);
 
-		if (!sig_only) {
+		if (!user_only) {
 			wq_busy = freeze_workqueues_busy();
 			todo += wq_busy;
 		}