5 files changed, 46 insertions, 22 deletions

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index a990824c8604..7ab5eafea8b2 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -57,7 +57,8 @@ static struct tracer_flags blk_tracer_flags = {
 };
 
 /* Global reference count of probes */
-static atomic_t blk_probes_ref = ATOMIC_INIT(0);
+static DEFINE_MUTEX(blk_probe_mutex);
+static int blk_probes_ref;
 
 static void blk_register_tracepoints(void);
 static void blk_unregister_tracepoints(void);
@@ -300,11 +301,26 @@ static void blk_trace_free(struct blk_trace *bt)
 	kfree(bt);
 }
 
+static void get_probe_ref(void)
+{
+	mutex_lock(&blk_probe_mutex);
+	if (++blk_probes_ref == 1)
+		blk_register_tracepoints();
+	mutex_unlock(&blk_probe_mutex);
+}
+
+static void put_probe_ref(void)
+{
+	mutex_lock(&blk_probe_mutex);
+	if (!--blk_probes_ref)
+		blk_unregister_tracepoints();
+	mutex_unlock(&blk_probe_mutex);
+}
+
 static void blk_trace_cleanup(struct blk_trace *bt)
 {
 	blk_trace_free(bt);
-	if (atomic_dec_and_test(&blk_probes_ref))
-		blk_unregister_tracepoints();
+	put_probe_ref();
 }
 
 int blk_trace_remove(struct request_queue *q)
@@ -522,8 +538,7 @@ int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 	if (cmpxchg(&q->blk_trace, NULL, bt))
 		goto err;
 
-	if (atomic_inc_return(&blk_probes_ref) == 1)
-		blk_register_tracepoints();
+	get_probe_ref();
 
 	return 0;
 err:
@@ -1466,9 +1481,7 @@ static int blk_trace_remove_queue(struct request_queue *q)
 	if (bt == NULL)
 		return -EINVAL;
 
-	if (atomic_dec_and_test(&blk_probes_ref))
-		blk_unregister_tracepoints();
-
+	put_probe_ref();
 	blk_trace_free(bt);
 	return 0;
 }
@@ -1499,8 +1512,7 @@ static int blk_trace_setup_queue(struct request_queue *q,
 	if (cmpxchg(&q->blk_trace, NULL, bt))
 		goto free_bt;
 
-	if (atomic_inc_return(&blk_probes_ref) == 1)
-		blk_register_tracepoints();
+	get_probe_ref();
 	return 0;
 
 free_bt:
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index fc0051fd672d..ac758a53fcea 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3845,7 +3845,6 @@ __unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
 		func_g.type = filter_parse_regex(glob, strlen(glob),
 						 &func_g.search, &not);
 		func_g.len = strlen(func_g.search);
-		func_g.search = glob;
 
 		/* we do not support '!' for function probes */
 		if (WARN_ON(not))
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 1275175b0946..d9cd6191760b 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -280,6 +280,8 @@ EXPORT_SYMBOL_GPL(ring_buffer_event_data);
 /* Missed count stored at end */
 #define RB_MISSED_STORED	(1 << 30)
 
+#define RB_MISSED_FLAGS		(RB_MISSED_EVENTS|RB_MISSED_STORED)
+
 struct buffer_data_page {
 	u64		 time_stamp;	/* page time stamp */
 	local_t		 commit;	/* write committed index */
@@ -331,7 +333,9 @@ static void rb_init_page(struct buffer_data_page *bpage)
  */
 size_t ring_buffer_page_len(void *page)
 {
-	return local_read(&((struct buffer_data_page *)page)->commit)
+	struct buffer_data_page *bpage = page;
+
+	return (local_read(&bpage->commit) & ~RB_MISSED_FLAGS)
 		+ BUF_PAGE_HDR_SIZE;
 }
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 61d0960559c8..8aef4e63ac57 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5754,7 +5754,7 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 		.spd_release	= buffer_spd_release,
 	};
 	struct buffer_ref *ref;
-	int entries, size, i;
+	int entries, i;
 	ssize_t ret = 0;
 
 #ifdef CONFIG_TRACER_MAX_TRACE
@@ -5805,14 +5805,6 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 			break;
 		}
 
-		/*
-		 * zero out any left over data, this is going to
-		 * user land.
-		 */
-		size = ring_buffer_page_len(ref->page);
-		if (size < PAGE_SIZE)
-			memset(ref->page + size, 0, PAGE_SIZE - size);
-
 		page = virt_to_page(ref->page);
 
 		spd.pages[i] = page;
@@ -6539,6 +6531,7 @@ allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size
 	buf->data = alloc_percpu(struct trace_array_cpu);
 	if (!buf->data) {
 		ring_buffer_free(buf->buffer);
+		buf->buffer = NULL;
 		return -ENOMEM;
 	}
 
@@ -6562,7 +6555,9 @@ static int allocate_trace_buffers(struct trace_array *tr, int size)
 				    allocate_snapshot ? size : 1);
 	if (WARN_ON(ret)) {
 		ring_buffer_free(tr->trace_buffer.buffer);
+		tr->trace_buffer.buffer = NULL;
 		free_percpu(tr->trace_buffer.data);
+		tr->trace_buffer.data = NULL;
 		return -ENOMEM;
 	}
 	tr->allocated_snapshot = allocate_snapshot;
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 996f0fd34312..ba5392807912 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2300,6 +2300,7 @@ void trace_event_enum_update(struct trace_enum_map **map, int len)
 {
 	struct trace_event_call *call, *p;
 	const char *last_system = NULL;
+	bool first = false;
 	int last_i;
 	int i;
 
@@ -2307,15 +2308,28 @@ void trace_event_enum_update(struct trace_enum_map **map, int len)
 	list_for_each_entry_safe(call, p, &ftrace_events, list) {
 		/* events are usually grouped together with systems */
 		if (!last_system || call->class->system != last_system) {
+			first = true;
 			last_i = 0;
 			last_system = call->class->system;
 		}
 
+		/*
+		 * Since calls are grouped by systems, the likelyhood that the
+		 * next call in the iteration belongs to the same system as the
+		 * previous call is high. As an optimization, we skip seaching
+		 * for a map[] that matches the call's system if the last call
+		 * was from the same system. That's what last_i is for. If the
+		 * call has the same system as the previous call, then last_i
+		 * will be the index of the first map[] that has a matching
+		 * system.
+		 */
 		for (i = last_i; i < len; i++) {
 			if (call->class->system == map[i]->system) {
 				/* Save the first system if need be */
-				if (!last_i)
+				if (first) {
 					last_i = i;
+					first = false;
+				}
 				update_event_printk(call, map[i]);
 			}
 		}