locking, sched: Annotate thread_group_cputimer as raw

The thread_group_cputimer lock can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

include/linux/init_task.h

@@ -42,7 +42,7 @@ extern struct fs_struct init_fs;
 	.cputimer	= { 						\
 		.cputime = INIT_CPUTIME,				\
 		.running = 0,						\
-		.lock = __SPIN_LOCK_UNLOCKED(sig.cputimer.lock),	\
+		.lock = __RAW_SPIN_LOCK_UNLOCKED(sig.cputimer.lock),	\
 	},								\
 	.cred_guard_mutex =						\
 		 __MUTEX_INITIALIZER(sig.cred_guard_mutex),		\

include/linux/sched.h

@@ -510,7 +510,7 @@ struct task_cputime {
 struct thread_group_cputimer {
 	struct task_cputime cputime;
 	int running;
-	spinlock_t lock;
+	raw_spinlock_t lock;
 };
 
 #include <linux/rwsem.h>
@@ -2566,7 +2566,7 @@ void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times);
 
 static inline void thread_group_cputime_init(struct signal_struct *sig)
 {
-	spin_lock_init(&sig->cputimer.lock);
+	raw_spin_lock_init(&sig->cputimer.lock);
 }
 
 /*

kernel/posix-cpu-timers.c

@@ -274,7 +274,7 @@ void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
 	struct task_cputime sum;
 	unsigned long flags;
 
-	spin_lock_irqsave(&cputimer->lock, flags);
+	raw_spin_lock_irqsave(&cputimer->lock, flags);
 	if (!cputimer->running) {
 		cputimer->running = 1;
 		/*
@@ -287,7 +287,7 @@ void thread_group_cputimer(struct task_struct *tsk, struct task_cputime *times)
 		update_gt_cputime(&cputimer->cputime, &sum);
 	}
 	*times = cputimer->cputime;
-	spin_unlock_irqrestore(&cputimer->lock, flags);
+	raw_spin_unlock_irqrestore(&cputimer->lock, flags);
 }
 
 /*
@@ -997,9 +997,9 @@ static void stop_process_timers(struct signal_struct *sig)
 	struct thread_group_cputimer *cputimer = &sig->cputimer;
 	unsigned long flags;
 
-	spin_lock_irqsave(&cputimer->lock, flags);
+	raw_spin_lock_irqsave(&cputimer->lock, flags);
 	cputimer->running = 0;
-	spin_unlock_irqrestore(&cputimer->lock, flags);
+	raw_spin_unlock_irqrestore(&cputimer->lock, flags);
 }
 
 static u32 onecputick;
@@ -1289,9 +1289,9 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
 	if (sig->cputimer.running) {
 		struct task_cputime group_sample;
 
-		spin_lock(&sig->cputimer.lock);
+		raw_spin_lock(&sig->cputimer.lock);
 		group_sample = sig->cputimer.cputime;
-		spin_unlock(&sig->cputimer.lock);
+		raw_spin_unlock(&sig->cputimer.lock);
 
 		if (task_cputime_expired(&group_sample, &sig->cputime_expires))
 			return 1;

kernel/sched_stats.h

@@ -282,10 +282,10 @@ static inline void account_group_user_time(struct task_struct *tsk,
 	if (!cputimer->running)
 		return;
 
-	spin_lock(&cputimer->lock);
+	raw_spin_lock(&cputimer->lock);
 	cputimer->cputime.utime =
 		cputime_add(cputimer->cputime.utime, cputime);
-	spin_unlock(&cputimer->lock);
+	raw_spin_unlock(&cputimer->lock);
 }
 
 /**
@@ -306,10 +306,10 @@ static inline void account_group_system_time(struct task_struct *tsk,
 	if (!cputimer->running)
 		return;
 
-	spin_lock(&cputimer->lock);
+	raw_spin_lock(&cputimer->lock);
 	cputimer->cputime.stime =
 		cputime_add(cputimer->cputime.stime, cputime);
-	spin_unlock(&cputimer->lock);
+	raw_spin_unlock(&cputimer->lock);
 }
 
 /**
@@ -330,7 +330,7 @@ static inline void account_group_exec_runtime(struct task_struct *tsk,
 	if (!cputimer->running)
 		return;
 
-	spin_lock(&cputimer->lock);
+	raw_spin_lock(&cputimer->lock);
 	cputimer->cputime.sum_exec_runtime += ns;
-	spin_unlock(&cputimer->lock);
+	raw_spin_unlock(&cputimer->lock);
 }