freezer: rename thaw_process() to __thaw_task() and simplify the implementation
thaw_process() now has only internal users - system and cgroup
freezers. Remove the unnecessary return value, rename, unexport and
collapse __thaw_process() into it. This will help further updates to
the freezer code.
-v3: oom_kill grew a use of thaw_process() while this patch was
pending. Convert it to use __thaw_task() for now. In the longer
term, this should be handled by allowing tasks to die if killed
even if it's frozen.
-v2: minor style update as suggested by Matt.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Paul Menage <menage@google.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
diff --git a/include/linux/freezer.h b/include/linux/freezer.h
index d02b784..ba4f512 100644
--- a/include/linux/freezer.h
+++ b/include/linux/freezer.h
@@ -45,7 +45,7 @@
}
/* Takes and releases task alloc lock using task_lock() */
-extern int thaw_process(struct task_struct *p);
+extern void __thaw_task(struct task_struct *t);
extern bool __refrigerator(bool check_kthr_stop);
extern int freeze_processes(void);
@@ -178,7 +178,6 @@
static inline int freezing(struct task_struct *p) { return 0; }
static inline void set_freeze_flag(struct task_struct *p) {}
static inline void clear_freeze_flag(struct task_struct *p) {}
-static inline int thaw_process(struct task_struct *p) { return 1; }
static inline bool __refrigerator(bool check_kthr_stop) { return false; }
static inline int freeze_processes(void) { return -ENOSYS; }
diff --git a/kernel/cgroup_freezer.c b/kernel/cgroup_freezer.c
index 5e828a2..a6d405a 100644
--- a/kernel/cgroup_freezer.c
+++ b/kernel/cgroup_freezer.c
@@ -130,7 +130,7 @@
* write_lock css_set_lock (cgroup iterator start)
* task->alloc_lock
* read_lock css_set_lock (cgroup iterator start)
- * task->alloc_lock (inside thaw_process(), prevents race with refrigerator())
+ * task->alloc_lock (inside __thaw_task(), prevents race with refrigerator())
* sighand->siglock
*/
static struct cgroup_subsys_state *freezer_create(struct cgroup_subsys *ss,
@@ -300,9 +300,8 @@
struct task_struct *task;
cgroup_iter_start(cgroup, &it);
- while ((task = cgroup_iter_next(cgroup, &it))) {
- thaw_process(task);
- }
+ while ((task = cgroup_iter_next(cgroup, &it)))
+ __thaw_task(task);
cgroup_iter_end(cgroup, &it);
freezer->state = CGROUP_THAWED;
diff --git a/kernel/freezer.c b/kernel/freezer.c
index b83c30e..c851d58 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -145,18 +145,8 @@
}
}
-static int __thaw_process(struct task_struct *p)
-{
- if (frozen(p)) {
- p->flags &= ~PF_FROZEN;
- return 1;
- }
- clear_freeze_flag(p);
- return 0;
-}
-
/*
- * Wake up a frozen process
+ * Wake up a frozen task
*
* task_lock() is needed to prevent the race with refrigerator() which may
* occur if the freezing of tasks fails. Namely, without the lock, if the
@@ -164,15 +154,18 @@
* refrigerator() could call frozen_process(), in which case the task would be
* frozen and no one would thaw it.
*/
-int thaw_process(struct task_struct *p)
+void __thaw_task(struct task_struct *p)
{
+ bool was_frozen;
+
task_lock(p);
- if (__thaw_process(p) == 1) {
- task_unlock(p);
- wake_up_process(p);
- return 1;
- }
+ was_frozen = frozen(p);
+ if (was_frozen)
+ p->flags &= ~PF_FROZEN;
+ else
+ clear_freeze_flag(p);
task_unlock(p);
- return 0;
+
+ if (was_frozen)
+ wake_up_process(p);
}
-EXPORT_SYMBOL(thaw_process);
diff --git a/kernel/power/process.c b/kernel/power/process.c
index addbbe5..fe27872 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -186,7 +186,7 @@
if (cgroup_freezing_or_frozen(p))
continue;
- thaw_process(p);
+ __thaw_task(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
}
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 76f2c5a..3134ee2 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -328,7 +328,7 @@
*/
if (test_tsk_thread_flag(p, TIF_MEMDIE)) {
if (unlikely(frozen(p)))
- thaw_process(p);
+ __thaw_task(p);
return ERR_PTR(-1UL);
}
if (!p->mm)
