locking, tracing: Annotate tracing locks as raw

The tracing locks 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: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/trace/ring_buffer.c

@@ -478,7 +478,7 @@ struct ring_buffer_per_cpu {
 	int				cpu;
 	atomic_t			record_disabled;
 	struct ring_buffer		*buffer;
-	spinlock_t			reader_lock;	/* serialize readers */
+	raw_spinlock_t			reader_lock;	/* serialize readers */
 	arch_spinlock_t			lock;
 	struct lock_class_key		lock_key;
 	struct list_head		*pages;
@@ -1062,7 +1062,7 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
 
 	cpu_buffer->cpu = cpu;
 	cpu_buffer->buffer = buffer;
-	spin_lock_init(&cpu_buffer->reader_lock);
+	raw_spin_lock_init(&cpu_buffer->reader_lock);
 	lockdep_set_class(&cpu_buffer->reader_lock, buffer->reader_lock_key);
 	cpu_buffer->lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
 
@@ -1259,7 +1259,7 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
 	struct list_head *p;
 	unsigned i;
 
-	spin_lock_irq(&cpu_buffer->reader_lock);
+	raw_spin_lock_irq(&cpu_buffer->reader_lock);
 	rb_head_page_deactivate(cpu_buffer);
 
 	for (i = 0; i < nr_pages; i++) {
@@ -1277,7 +1277,7 @@ rb_remove_pages(struct ring_buffer_per_cpu *cpu_buffer, unsigned nr_pages)
 	rb_check_pages(cpu_buffer);
 
 out:
-	spin_unlock_irq(&cpu_buffer->reader_lock);
+	raw_spin_unlock_irq(&cpu_buffer->reader_lock);
 }
 
 static void
@@ -1288,7 +1288,7 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
 	struct list_head *p;
 	unsigned i;
 
-	spin_lock_irq(&cpu_buffer->reader_lock);
+	raw_spin_lock_irq(&cpu_buffer->reader_lock);
 	rb_head_page_deactivate(cpu_buffer);
 
 	for (i = 0; i < nr_pages; i++) {
@@ -1303,7 +1303,7 @@ rb_insert_pages(struct ring_buffer_per_cpu *cpu_buffer,
 	rb_check_pages(cpu_buffer);
 
 out:
-	spin_unlock_irq(&cpu_buffer->reader_lock);
+	raw_spin_unlock_irq(&cpu_buffer->reader_lock);
 }
 
 /**
@@ -2804,9 +2804,9 @@ void ring_buffer_iter_reset(struct ring_buffer_iter *iter)
 
 	cpu_buffer = iter->cpu_buffer;
 
-	spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
 	rb_iter_reset(iter);
-	spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 }
 EXPORT_SYMBOL_GPL(ring_buffer_iter_reset);
 
@@ -3265,12 +3265,12 @@ ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts,
  again:
 	local_irq_save(flags);
 	if (dolock)
-		spin_lock(&cpu_buffer->reader_lock);
+		raw_spin_lock(&cpu_buffer->reader_lock);
 	event = rb_buffer_peek(cpu_buffer, ts, lost_events);
 	if (event && event->type_len == RINGBUF_TYPE_PADDING)
 		rb_advance_reader(cpu_buffer);
 	if (dolock)
-		spin_unlock(&cpu_buffer->reader_lock);
+		raw_spin_unlock(&cpu_buffer->reader_lock);
 	local_irq_restore(flags);
 
 	if (event && event->type_len == RINGBUF_TYPE_PADDING)
@@ -3295,9 +3295,9 @@ ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
 	unsigned long flags;
 
  again:
-	spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
 	event = rb_iter_peek(iter, ts);
-	spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
 	if (event && event->type_len == RINGBUF_TYPE_PADDING)
 		goto again;
@@ -3337,7 +3337,7 @@ ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts,
 	cpu_buffer = buffer->buffers[cpu];
 	local_irq_save(flags);
 	if (dolock)
-		spin_lock(&cpu_buffer->reader_lock);
+		raw_spin_lock(&cpu_buffer->reader_lock);
 
 	event = rb_buffer_peek(cpu_buffer, ts, lost_events);
 	if (event) {
@@ -3346,7 +3346,7 @@ ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts,
 	}
 
 	if (dolock)
-		spin_unlock(&cpu_buffer->reader_lock);
+		raw_spin_unlock(&cpu_buffer->reader_lock);
 	local_irq_restore(flags);
 
  out:
@@ -3438,11 +3438,11 @@ ring_buffer_read_start(struct ring_buffer_iter *iter)
 
 	cpu_buffer = iter->cpu_buffer;
 
-	spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
 	arch_spin_lock(&cpu_buffer->lock);
 	rb_iter_reset(iter);
 	arch_spin_unlock(&cpu_buffer->lock);
-	spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 }
 EXPORT_SYMBOL_GPL(ring_buffer_read_start);
 
@@ -3477,7 +3477,7 @@ ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts)
 	struct ring_buffer_per_cpu *cpu_buffer = iter->cpu_buffer;
 	unsigned long flags;
 
-	spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
  again:
 	event = rb_iter_peek(iter, ts);
 	if (!event)
@@ -3488,7 +3488,7 @@ ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts)
 
 	rb_advance_iter(iter);
  out:
-	spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
 	return event;
 }
@@ -3557,7 +3557,7 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu)
 
 	atomic_inc(&cpu_buffer->record_disabled);
 
-	spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
 
 	if (RB_WARN_ON(cpu_buffer, local_read(&cpu_buffer->committing)))
 		goto out;
@@ -3569,7 +3569,7 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu)
 	arch_spin_unlock(&cpu_buffer->lock);
 
  out:
-	spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
 	atomic_dec(&cpu_buffer->record_disabled);
 }
@@ -3607,10 +3607,10 @@ int ring_buffer_empty(struct ring_buffer *buffer)
 		cpu_buffer = buffer->buffers[cpu];
 		local_irq_save(flags);
 		if (dolock)
-			spin_lock(&cpu_buffer->reader_lock);
+			raw_spin_lock(&cpu_buffer->reader_lock);
 		ret = rb_per_cpu_empty(cpu_buffer);
 		if (dolock)
-			spin_unlock(&cpu_buffer->reader_lock);
+			raw_spin_unlock(&cpu_buffer->reader_lock);
 		local_irq_restore(flags);
 
 		if (!ret)
@@ -3641,10 +3641,10 @@ int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu)
 	cpu_buffer = buffer->buffers[cpu];
 	local_irq_save(flags);
 	if (dolock)
-		spin_lock(&cpu_buffer->reader_lock);
+		raw_spin_lock(&cpu_buffer->reader_lock);
 	ret = rb_per_cpu_empty(cpu_buffer);
 	if (dolock)
-		spin_unlock(&cpu_buffer->reader_lock);
+		raw_spin_unlock(&cpu_buffer->reader_lock);
 	local_irq_restore(flags);
 
 	return ret;
@@ -3841,7 +3841,7 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
 	if (!bpage)
 		goto out;
 
-	spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+	raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
 
 	reader = rb_get_reader_page(cpu_buffer);
 	if (!reader)
@@ -3964,7 +3964,7 @@ int ring_buffer_read_page(struct ring_buffer *buffer,
 		memset(&bpage->data[commit], 0, BUF_PAGE_SIZE - commit);
 
  out_unlock:
-	spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+	raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
 
  out:
 	return ret;

kernel/trace/trace.c

@@ -341,7 +341,7 @@ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |
 	TRACE_ITER_GRAPH_TIME | TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE;
 
 static int trace_stop_count;
-static DEFINE_SPINLOCK(tracing_start_lock);
+static DEFINE_RAW_SPINLOCK(tracing_start_lock);
 
 static void wakeup_work_handler(struct work_struct *work)
 {
@@ -960,7 +960,7 @@ void tracing_start(void)
 	if (tracing_disabled)
 		return;
 
-	spin_lock_irqsave(&tracing_start_lock, flags);
+	raw_spin_lock_irqsave(&tracing_start_lock, flags);
 	if (--trace_stop_count) {
 		if (trace_stop_count < 0) {
 			/* Someone screwed up their debugging */
@@ -985,7 +985,7 @@ void tracing_start(void)
 
 	ftrace_start();
  out:
-	spin_unlock_irqrestore(&tracing_start_lock, flags);
+	raw_spin_unlock_irqrestore(&tracing_start_lock, flags);
 }
 
 /**
@@ -1000,7 +1000,7 @@ void tracing_stop(void)
 	unsigned long flags;
 
 	ftrace_stop();
-	spin_lock_irqsave(&tracing_start_lock, flags);
+	raw_spin_lock_irqsave(&tracing_start_lock, flags);
 	if (trace_stop_count++)
 		goto out;
 
@@ -1018,7 +1018,7 @@ void tracing_stop(void)
 	arch_spin_unlock(&ftrace_max_lock);
 
  out:
-	spin_unlock_irqrestore(&tracing_start_lock, flags);
+	raw_spin_unlock_irqrestore(&tracing_start_lock, flags);
 }
 
 void trace_stop_cmdline_recording(void);

kernel/trace/trace_irqsoff.c

@@ -23,7 +23,7 @@ static int				tracer_enabled __read_mostly;
 
 static DEFINE_PER_CPU(int, tracing_cpu);
 
-static DEFINE_SPINLOCK(max_trace_lock);
+static DEFINE_RAW_SPINLOCK(max_trace_lock);
 
 enum {
 	TRACER_IRQS_OFF		= (1 << 1),
@@ -321,7 +321,7 @@ check_critical_timing(struct trace_array *tr,
 	if (!report_latency(delta))
 		goto out;
 
-	spin_lock_irqsave(&max_trace_lock, flags);
+	raw_spin_lock_irqsave(&max_trace_lock, flags);
 
 	/* check if we are still the max latency */
 	if (!report_latency(delta))
@@ -344,7 +344,7 @@ check_critical_timing(struct trace_array *tr,
 	max_sequence++;
 
 out_unlock:
-	spin_unlock_irqrestore(&max_trace_lock, flags);
+	raw_spin_unlock_irqrestore(&max_trace_lock, flags);
 
 out:
 	data->critical_sequence = max_sequence;