sched/headers: Move the task_lock()/unlock() APIs to <linux/sched/task.h>

The task_lock()/task_unlock() APIs are not realated to core scheduling,
they are task lifetime APIs, i.e. they belong into <linux/sched/task.h>.

Move them.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/sched.h

@@ -1526,26 +1526,6 @@ static inline unsigned long wait_task_inactive(struct task_struct *p,
 }
 #endif
 
-/*
- * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
- * subscriptions and synchronises with wait4().  Also used in procfs.  Also
- * pins the final release of task.io_context.  Also protects ->cpuset and
- * ->cgroup.subsys[]. And ->vfork_done.
- *
- * Nests both inside and outside of read_lock(&tasklist_lock).
- * It must not be nested with write_lock_irq(&tasklist_lock),
- * neither inside nor outside.
- */
-static inline void task_lock(struct task_struct *p)
-{
-	spin_lock(&p->alloc_lock);
-}
-
-static inline void task_unlock(struct task_struct *p)
-{
-	spin_unlock(&p->alloc_lock);
-}
-
 /* set thread flags in other task's structures
  * - see asm/thread_info.h for TIF_xxxx flags available
  */

include/linux/sched/task.h

@@ -91,4 +91,24 @@ static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
 }
 #endif
 
+/*
+ * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
+ * subscriptions and synchronises with wait4().  Also used in procfs.  Also
+ * pins the final release of task.io_context.  Also protects ->cpuset and
+ * ->cgroup.subsys[]. And ->vfork_done.
+ *
+ * Nests both inside and outside of read_lock(&tasklist_lock).
+ * It must not be nested with write_lock_irq(&tasklist_lock),
+ * neither inside nor outside.
+ */
+static inline void task_lock(struct task_struct *p)
+{
+	spin_lock(&p->alloc_lock);
+}
+
+static inline void task_unlock(struct task_struct *p)
+{
+	spin_unlock(&p->alloc_lock);
+}
+
 #endif /* _LINUX_SCHED_TASK_H */

kernel/cgroup/cgroup-v1.c

@@ -6,6 +6,7 @@
 #include <linux/delay.h>
 #include <linux/mm.h>
 #include <linux/sched/signal.h>
+#include <linux/sched/task.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/delayacct.h>

kernel/cgroup/namespace.c

@@ -1,6 +1,6 @@
 #include "cgroup-internal.h"
 
-#include <linux/sched.h>
+#include <linux/sched/task.h>
 #include <linux/slab.h>
 #include <linux/nsproxy.h>
 #include <linux/proc_ns.h>