posix_cpu_timer: Convert cputimer->running to bool

In the next patch in this series, a new field 'checking_timer' will
be added to 'struct thread_group_cputimer'. Both this and the
existing 'running' integer field are just used as boolean values. To
save space in the structure, we can make both of these fields booleans.

This is a preparatory patch to convert the existing running integer
field to a boolean.

Suggested-by: George Spelvin <linux@horizon.com>
Signed-off-by: Jason Low <jason.low2@hp.com>
Reviewed: George Spelvin <linux@horizon.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: hideaki.kimura@hpe.com
Cc: terry.rudd@hpe.com
Cc: scott.norton@hpe.com
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1444849677-29330-4-git-send-email-jason.low2@hp.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

include/linux/init_task.h

@@ -59,7 +59,7 @@ extern struct fs_struct init_fs;
 	.rlim		= INIT_RLIMITS,					\
 	.cputimer	= { 						\
 		.cputime_atomic	= INIT_CPUTIME_ATOMIC,			\
-		.running	= 0,					\
+		.running	= false,				\
 	},								\
 	INIT_PREV_CPUTIME(sig)						\
 	.cred_guard_mutex =						\

include/linux/sched.h

@@ -617,15 +617,15 @@ struct task_cputime_atomic {
 /**
  * struct thread_group_cputimer - thread group interval timer counts
  * @cputime_atomic:	atomic thread group interval timers.
- * @running:		non-zero when there are timers running and
- * 			@cputime receives updates.
+ * @running:		true when there are timers running and
+ *			@cputime_atomic receives updates.
  *
  * This structure contains the version of task_cputime, above, that is
  * used for thread group CPU timer calculations.
  */
 struct thread_group_cputimer {
 	struct task_cputime_atomic cputime_atomic;
-	int running;
+	bool running;
 };
 
 #include <linux/rwsem.h>

kernel/fork.c

@@ -1101,7 +1101,7 @@ static void posix_cpu_timers_init_group(struct signal_struct *sig)
 	cpu_limit = READ_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
 	if (cpu_limit != RLIM_INFINITY) {
 		sig->cputime_expires.prof_exp = secs_to_cputime(cpu_limit);
-		sig->cputimer.running = 1;
+		sig->cputimer.running = true;
 	}
 
 	/* The timer lists. */

kernel/time/posix-cpu-timers.c

@@ -249,7 +249,7 @@ void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
 		 * but barriers are not required because update_gt_cputime()
 		 * can handle concurrent updates.
 		 */
-		WRITE_ONCE(cputimer->running, 1);
+		WRITE_ONCE(cputimer->running, true);
 	}
 	sample_cputime_atomic(times, &cputimer->cputime_atomic);
 }
@@ -918,7 +918,7 @@ static inline void stop_process_timers(struct signal_struct *sig)
 	struct thread_group_cputimer *cputimer = &sig->cputimer;
 
 	/* Turn off cputimer->running. This is done without locking. */
-	WRITE_ONCE(cputimer->running, 0);
+	WRITE_ONCE(cputimer->running, false);
 }
 
 static u32 onecputick;