locking, latencytop: Annotate latency_lock as raw

The latency_lock is lock can be taken in the guts of the
scheduler code 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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/latencytop.c b/kernel/latencytop.c
index 376066e..4ac8ebf 100644 (file)
--- a/kernel/latencytop.c
+++ b/kernel/latencytop.c
@@ -58,7 +58,7 @@
 #include <linux/list.h>
 #include <linux/stacktrace.h>
 
-static DEFINE_SPINLOCK(latency_lock);
+static DEFINE_RAW_SPINLOCK(latency_lock);
 
 #define MAXLR 128
 static struct latency_record latency_record[MAXLR];
@@ -72,19 +72,19 @@ void clear_all_latency_tracing(struct task_struct *p)
        if (!latencytop_enabled)
                return;
 
-       spin_lock_irqsave(&latency_lock, flags);
+       raw_spin_lock_irqsave(&latency_lock, flags);
        memset(&p->latency_record, 0, sizeof(p->latency_record));
        p->latency_record_count = 0;
-       spin_unlock_irqrestore(&latency_lock, flags);
+       raw_spin_unlock_irqrestore(&latency_lock, flags);
 }
 
 static void clear_global_latency_tracing(void)
 {
        unsigned long flags;
 
-       spin_lock_irqsave(&latency_lock, flags);
+       raw_spin_lock_irqsave(&latency_lock, flags);
        memset(&latency_record, 0, sizeof(latency_record));
-       spin_unlock_irqrestore(&latency_lock, flags);
+       raw_spin_unlock_irqrestore(&latency_lock, flags);
 }
 
 static void __sched
@@ -190,7 +190,7 @@ __account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
        lat.max = usecs;
        store_stacktrace(tsk, &lat);
 
-       spin_lock_irqsave(&latency_lock, flags);
+       raw_spin_lock_irqsave(&latency_lock, flags);
 
        account_global_scheduler_latency(tsk, &lat);
 
@@ -231,7 +231,7 @@ __account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
        memcpy(&tsk->latency_record[i], &lat, sizeof(struct latency_record));
 
 out_unlock:
-       spin_unlock_irqrestore(&latency_lock, flags);
+       raw_spin_unlock_irqrestore(&latency_lock, flags);
 }
 
 static int lstats_show(struct seq_file *m, void *v)