Merge tag 'trace-v3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:
 "The updates included in this pull request for ftrace are:

   o Several clean ups to the code

     One such clean up was to convert to 64 bit time keeping, in the
     ring buffer benchmark code.

   o Adding of __print_array() helper macro for TRACE_EVENT()

   o Updating the sample/trace_events/ to add samples of different ways
     to make trace events.  Lots of features have been added since the
     sample code was made, and these features are mostly unknown.
     Developers have been making their own hacks to do things that are
     already available.

   o Performance improvements.  Most notably, I found a performance bug
     where a waiter that is waiting for a full page from the ring buffer
     will see that a full page is not available, and go to sleep.  The
     sched event caused by it going to sleep would cause it to wake up
     again.  It would see that there was still not a full page, and go
     back to sleep again, and that would wake it up again, until finally
     it would see a full page.  This change has been marked for stable.

  Other improvements include removing global locks from fast paths"

* tag 'trace-v3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ring-buffer: Do not wake up a splice waiter when page is not full
  tracing: Fix unmapping loop in tracing_mark_write
  tracing: Add samples of DECLARE_EVENT_CLASS() and DEFINE_EVENT()
  tracing: Add TRACE_EVENT_FN example
  tracing: Add TRACE_EVENT_CONDITION sample
  tracing: Update the TRACE_EVENT fields available in the sample code
  tracing: Separate out initializing top level dir from instances
  tracing: Make tracing_init_dentry_tr() static
  trace: Use 64-bit timekeeping
  tracing: Add array printing helper
  tracing: Remove newline from trace_printk warning banner
  tracing: Use IS_ERR() check for return value of tracing_init_dentry()
  tracing: Remove unneeded includes of debugfs.h and fs.h
  tracing: Remove taking of trace_types_lock in pipe files
  tracing: Add ref count to tracer for when they are being read by pipe

19 files changed, 175 insertions, 150 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 224e768bdc7..45e5cb143d1 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5456,7 +5456,7 @@ static __init int ftrace_init_debugfs(void)
 	struct dentry *d_tracer;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	ftrace_init_dyn_debugfs(d_tracer);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 7a4104cb95c..5040d44fe5a 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -9,7 +9,6 @@
 #include <linux/trace_seq.h>
 #include <linux/spinlock.h>
 #include <linux/irq_work.h>
-#include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/hardirq.h>
 #include <linux/kthread.h>	/* for self test */
@@ -23,7 +22,6 @@
 #include <linux/hash.h>
 #include <linux/list.h>
 #include <linux/cpu.h>
-#include <linux/fs.h>
 
 #include <asm/local.h>
 
@@ -447,7 +445,10 @@ int ring_buffer_print_page_header(struct trace_seq *s)
 struct rb_irq_work {
 	struct irq_work			work;
 	wait_queue_head_t		waiters;
+	wait_queue_head_t		full_waiters;
 	bool				waiters_pending;
+	bool				full_waiters_pending;
+	bool				wakeup_full;
 };
 
 /*
@@ -529,6 +530,10 @@ static void rb_wake_up_waiters(struct irq_work *work)
 	struct rb_irq_work *rbwork = container_of(work, struct rb_irq_work, work);
 
 	wake_up_all(&rbwork->waiters);
+	if (rbwork->wakeup_full) {
+		rbwork->wakeup_full = false;
+		wake_up_all(&rbwork->full_waiters);
+	}
 }
 
 /**
@@ -553,9 +558,11 @@ int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full)
 	 * data in any cpu buffer, or a specific buffer, put the
 	 * caller on the appropriate wait queue.
 	 */
-	if (cpu == RING_BUFFER_ALL_CPUS)
+	if (cpu == RING_BUFFER_ALL_CPUS) {
 		work = &buffer->irq_work;
-	else {
+		/* Full only makes sense on per cpu reads */
+		full = false;
+	} else {
 		if (!cpumask_test_cpu(cpu, buffer->cpumask))
 			return -ENODEV;
 		cpu_buffer = buffer->buffers[cpu];
@@ -564,7 +571,10 @@ int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full)
 
 
 	while (true) {
-		prepare_to_wait(&work->waiters, &wait, TASK_INTERRUPTIBLE);
+		if (full)
+			prepare_to_wait(&work->full_waiters, &wait, TASK_INTERRUPTIBLE);
+		else
+			prepare_to_wait(&work->waiters, &wait, TASK_INTERRUPTIBLE);
 
 		/*
 		 * The events can happen in critical sections where
@@ -586,7 +596,10 @@ int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full)
 		 * that is necessary is that the wake up happens after
 		 * a task has been queued. It's OK for spurious wake ups.
 		 */
-		work->waiters_pending = true;
+		if (full)
+			work->full_waiters_pending = true;
+		else
+			work->waiters_pending = true;
 
 		if (signal_pending(current)) {
 			ret = -EINTR;
@@ -615,7 +628,10 @@ int ring_buffer_wait(struct ring_buffer *buffer, int cpu, bool full)
 		schedule();
 	}
 
-	finish_wait(&work->waiters, &wait);
+	if (full)
+		finish_wait(&work->full_waiters, &wait);
+	else
+		finish_wait(&work->waiters, &wait);
 
 	return ret;
 }
@@ -1230,6 +1246,7 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int nr_pages, int cpu)
 	init_completion(&cpu_buffer->update_done);
 	init_irq_work(&cpu_buffer->irq_work.work, rb_wake_up_waiters);
 	init_waitqueue_head(&cpu_buffer->irq_work.waiters);
+	init_waitqueue_head(&cpu_buffer->irq_work.full_waiters);
 
 	bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
 			    GFP_KERNEL, cpu_to_node(cpu));
@@ -2801,6 +2818,8 @@ static void rb_commit(struct ring_buffer_per_cpu *cpu_buffer,
 static __always_inline void
 rb_wakeups(struct ring_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
 {
+	bool pagebusy;
+
 	if (buffer->irq_work.waiters_pending) {
 		buffer->irq_work.waiters_pending = false;
 		/* irq_work_queue() supplies it's own memory barriers */
@@ -2812,6 +2831,15 @@ rb_wakeups(struct ring_buffer *buffer, struct ring_buffer_per_cpu *cpu_buffer)
 		/* irq_work_queue() supplies it's own memory barriers */
 		irq_work_queue(&cpu_buffer->irq_work.work);
 	}
+
+	pagebusy = cpu_buffer->reader_page == cpu_buffer->commit_page;
+
+	if (!pagebusy && cpu_buffer->irq_work.full_waiters_pending) {
+		cpu_buffer->irq_work.wakeup_full = true;
+		cpu_buffer->irq_work.full_waiters_pending = false;
+		/* irq_work_queue() supplies it's own memory barriers */
+		irq_work_queue(&cpu_buffer->irq_work.work);
+	}
 }
 
 /**
diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index 3f9e328c30b..13d945c0d03 100644
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -7,7 +7,7 @@
 #include <linux/completion.h>
 #include <linux/kthread.h>
 #include <linux/module.h>
-#include <linux/time.h>
+#include <linux/ktime.h>
 #include <asm/local.h>
 
 struct rb_page {
@@ -17,7 +17,7 @@ struct rb_page {
 };
 
 /* run time and sleep time in seconds */
-#define RUN_TIME	10
+#define RUN_TIME	10ULL
 #define SLEEP_TIME	10
 
 /* number of events for writer to wake up the reader */
@@ -212,8 +212,7 @@ static void ring_buffer_consumer(void)
 
 static void ring_buffer_producer(void)
 {
-	struct timeval start_tv;
-	struct timeval end_tv;
+	ktime_t start_time, end_time, timeout;
 	unsigned long long time;
 	unsigned long long entries;
 	unsigned long long overruns;
@@ -227,7 +226,8 @@ static void ring_buffer_producer(void)
 	 * make the system stall)
 	 */
 	trace_printk("Starting ring buffer hammer\n");
-	do_gettimeofday(&start_tv);
+	start_time = ktime_get();
+	timeout = ktime_add_ns(start_time, RUN_TIME * NSEC_PER_SEC);
 	do {
 		struct ring_buffer_event *event;
 		int *entry;
@@ -244,7 +244,7 @@ static void ring_buffer_producer(void)
 				ring_buffer_unlock_commit(buffer, event);
 			}
 		}
-		do_gettimeofday(&end_tv);
+		end_time = ktime_get();
 
 		cnt++;
 		if (consumer && !(cnt % wakeup_interval))
@@ -264,7 +264,7 @@ static void ring_buffer_producer(void)
 			cond_resched();
 #endif
 
-	} while (end_tv.tv_sec < (start_tv.tv_sec + RUN_TIME) && !kill_test);
+	} while (ktime_before(end_time, timeout) && !kill_test);
 	trace_printk("End ring buffer hammer\n");
 
 	if (consumer) {
@@ -280,9 +280,7 @@ static void ring_buffer_producer(void)
 		wait_for_completion(&read_done);
 	}
 
-	time = end_tv.tv_sec - start_tv.tv_sec;
-	time *= USEC_PER_SEC;
-	time += (long long)((long)end_tv.tv_usec - (long)start_tv.tv_usec);
+	time = ktime_us_delta(end_time, start_time);
 
 	entries = ring_buffer_entries(buffer);
 	overruns = ring_buffer_overruns(buffer);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4a9079b9f08..77b8dc52800 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2036,7 +2036,8 @@ void trace_printk_init_buffers(void)
 
 	/* trace_printk() is for debug use only. Don't use it in production. */
 
-	pr_warning("\n**********************************************************\n");
+	pr_warning("\n");
+	pr_warning("**********************************************************\n");
 	pr_warning("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
 	pr_warning("**                                                      **\n");
 	pr_warning("** trace_printk() being used. Allocating extra memory.  **\n");
@@ -4140,6 +4141,12 @@ static int tracing_set_tracer(struct trace_array *tr, const char *buf)
 		goto out;
 	}
 
+	/* If trace pipe files are being read, we can't change the tracer */
+	if (tr->current_trace->ref) {
+		ret = -EBUSY;
+		goto out;
+	}
+
 	trace_branch_disable();
 
 	tr->current_trace->enabled--;
@@ -4326,17 +4333,7 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
 	}
 
 	trace_seq_init(&iter->seq);
-
-	/*
-	 * We make a copy of the current tracer to avoid concurrent
-	 * changes on it while we are reading.
-	 */
-	iter->trace = kmalloc(sizeof(*iter->trace), GFP_KERNEL);
-	if (!iter->trace) {
-		ret = -ENOMEM;
-		goto fail;
-	}
-	*iter->trace = *tr->current_trace;
+	iter->trace = tr->current_trace;
 
 	if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
 		ret = -ENOMEM;
@@ -4363,6 +4360,8 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
 		iter->trace->pipe_open(iter);
 
 	nonseekable_open(inode, filp);
+
+	tr->current_trace->ref++;
 out:
 	mutex_unlock(&trace_types_lock);
 	return ret;
@@ -4382,6 +4381,8 @@ static int tracing_release_pipe(struct inode *inode, struct file *file)
 
 	mutex_lock(&trace_types_lock);
 
+	tr->current_trace->ref--;
+
 	if (iter->trace->pipe_close)
 		iter->trace->pipe_close(iter);
 
@@ -4389,7 +4390,6 @@ static int tracing_release_pipe(struct inode *inode, struct file *file)
 
 	free_cpumask_var(iter->started);
 	mutex_destroy(&iter->mutex);
-	kfree(iter->trace);
 	kfree(iter);
 
 	trace_array_put(tr);
@@ -4422,7 +4422,7 @@ tracing_poll_pipe(struct file *filp, poll_table *poll_table)
 	return trace_poll(iter, filp, poll_table);
 }
 
-/* Must be called with trace_types_lock mutex held. */
+/* Must be called with iter->mutex held. */
 static int tracing_wait_pipe(struct file *filp)
 {
 	struct trace_iterator *iter = filp->private_data;
@@ -4467,7 +4467,6 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
 		  size_t cnt, loff_t *ppos)
 {
 	struct trace_iterator *iter = filp->private_data;
-	struct trace_array *tr = iter->tr;
 	ssize_t sret;
 
 	/* return any leftover data */
@@ -4477,12 +4476,6 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
 
 	trace_seq_init(&iter->seq);
 
-	/* copy the tracer to avoid using a global lock all around */
-	mutex_lock(&trace_types_lock);
-	if (unlikely(iter->trace->name != tr->current_trace->name))
-		*iter->trace = *tr->current_trace;
-	mutex_unlock(&trace_types_lock);
-
 	/*
 	 * Avoid more than one consumer on a single file descriptor
 	 * This is just a matter of traces coherency, the ring buffer itself
@@ -4642,7 +4635,6 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
 		.ops		= &tracing_pipe_buf_ops,
 		.spd_release	= tracing_spd_release_pipe,
 	};
-	struct trace_array *tr = iter->tr;
 	ssize_t ret;
 	size_t rem;
 	unsigned int i;
@@ -4650,12 +4642,6 @@ static ssize_t tracing_splice_read_pipe(struct file *filp,
 	if (splice_grow_spd(pipe, &spd))
 		return -ENOMEM;
 
-	/* copy the tracer to avoid using a global lock all around */
-	mutex_lock(&trace_types_lock);
-	if (unlikely(iter->trace->name != tr->current_trace->name))
-		*iter->trace = *tr->current_trace;
-	mutex_unlock(&trace_types_lock);
-
 	mutex_lock(&iter->mutex);
 
 	if (iter->trace->splice_read) {
@@ -4942,7 +4928,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
 	*fpos += written;
 
  out_unlock:
-	for (i = 0; i < nr_pages; i++){
+	for (i = nr_pages - 1; i >= 0; i--) {
 		kunmap_atomic(map_page[i]);
 		put_page(pages[i]);
 	}
@@ -5331,6 +5317,8 @@ static int tracing_buffers_open(struct inode *inode, struct file *filp)
 
 	filp->private_data = info;
 
+	tr->current_trace->ref++;
+
 	mutex_unlock(&trace_types_lock);
 
 	ret = nonseekable_open(inode, filp);
@@ -5361,21 +5349,16 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
 	if (!count)
 		return 0;
 
-	mutex_lock(&trace_types_lock);
-
 #ifdef CONFIG_TRACER_MAX_TRACE
-	if (iter->snapshot && iter->tr->current_trace->use_max_tr) {
-		size = -EBUSY;
-		goto out_unlock;
-	}
+	if (iter->snapshot && iter->tr->current_trace->use_max_tr)
+		return -EBUSY;
 #endif
 
 	if (!info->spare)
 		info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
 							  iter->cpu_file);
-	size = -ENOMEM;
 	if (!info->spare)
-		goto out_unlock;
+		return -ENOMEM;
 
 	/* Do we have previous read data to read? */
 	if (info->read < PAGE_SIZE)
@@ -5391,21 +5374,16 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
 
 	if (ret < 0) {
 		if (trace_empty(iter)) {
-			if ((filp->f_flags & O_NONBLOCK)) {
-				size = -EAGAIN;
-				goto out_unlock;
-			}
-			mutex_unlock(&trace_types_lock);
+			if ((filp->f_flags & O_NONBLOCK))
+				return -EAGAIN;
+
 			ret = wait_on_pipe(iter, false);
-			mutex_lock(&trace_types_lock);
-			if (ret) {
-				size = ret;
-				goto out_unlock;
-			}
+			if (ret)
+				return ret;
+
 			goto again;
 		}
-		size = 0;
-		goto out_unlock;
+		return 0;
 	}
 
 	info->read = 0;
@@ -5415,18 +5393,14 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
 		size = count;
 
 	ret = copy_to_user(ubuf, info->spare + info->read, size);
-	if (ret == size) {
-		size = -EFAULT;
-		goto out_unlock;
-	}
+	if (ret == size)
+		return -EFAULT;
+
 	size -= ret;
 
 	*ppos += size;
 	info->read += size;
 
- out_unlock:
-	mutex_unlock(&trace_types_lock);
-
 	return size;
 }
 
@@ -5437,6 +5411,8 @@ static int tracing_buffers_release(struct inode *inode, struct file *file)
 
 	mutex_lock(&trace_types_lock);
 
+	iter->tr->current_trace->ref--;
+
 	__trace_array_put(iter->tr);
 
 	if (info->spare)
@@ -5522,30 +5498,20 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 	int entries, size, i;
 	ssize_t ret = 0;
 
-	mutex_lock(&trace_types_lock);
-
 #ifdef CONFIG_TRACER_MAX_TRACE
-	if (iter->snapshot && iter->tr->current_trace->use_max_tr) {
-		ret = -EBUSY;
-		goto out;
-	}
+	if (iter->snapshot && iter->tr->current_trace->use_max_tr)
+		return -EBUSY;
 #endif
 
-	if (splice_grow_spd(pipe, &spd)) {
-		ret = -ENOMEM;
-		goto out;
-	}
+	if (splice_grow_spd(pipe, &spd))
+		return -ENOMEM;
 
-	if (*ppos & (PAGE_SIZE - 1)) {
-		ret = -EINVAL;
-		goto out;
-	}
+	if (*ppos & (PAGE_SIZE - 1))
+		return -EINVAL;
 
 	if (len & (PAGE_SIZE - 1)) {
-		if (len < PAGE_SIZE) {
-			ret = -EINVAL;
-			goto out;
-		}
+		if (len < PAGE_SIZE)
+			return -EINVAL;
 		len &= PAGE_MASK;
 	}
 
@@ -5606,25 +5572,20 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 	/* did we read anything? */
 	if (!spd.nr_pages) {
 		if (ret)
-			goto out;
+			return ret;
+
+		if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
+			return -EAGAIN;
 
-		if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) {
-			ret = -EAGAIN;
-			goto out;
-		}
-		mutex_unlock(&trace_types_lock);
 		ret = wait_on_pipe(iter, true);
-		mutex_lock(&trace_types_lock);
 		if (ret)
-			goto out;
+			return ret;
 
 		goto again;
 	}
 
 	ret = splice_to_pipe(pipe, &spd);
 	splice_shrink_spd(&spd);
-out:
-	mutex_unlock(&trace_types_lock);
 
 	return ret;
 }
@@ -5854,28 +5815,11 @@ static __init int register_snapshot_cmd(void)
 static inline __init int register_snapshot_cmd(void) { return 0; }
 #endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
 
-struct dentry *tracing_init_dentry_tr(struct trace_array *tr)
+static struct dentry *tracing_get_dentry(struct trace_array *tr)
 {
-	if (tr->dir)
-		return tr->dir;
-
-	if (!debugfs_initialized())
-		return NULL;
-
-	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
-		tr->dir = debugfs_create_dir("tracing", NULL);
-
-	if (!tr->dir)
-		pr_warn_once("Could not create debugfs directory 'tracing'\n");
-
 	return tr->dir;
 }
 
-struct dentry *tracing_init_dentry(void)
-{
-	return tracing_init_dentry_tr(&global_trace);
-}
-
 static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
 {
 	struct dentry *d_tracer;
@@ -5883,8 +5827,8 @@ static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
 	if (tr->percpu_dir)
 		return tr->percpu_dir;
 
-	d_tracer = tracing_init_dentry_tr(tr);
-	if (!d_tracer)
+	d_tracer = tracing_get_dentry(tr);
+	if (IS_ERR(d_tracer))
 		return NULL;
 
 	tr->percpu_dir = debugfs_create_dir("per_cpu", d_tracer);
@@ -6086,8 +6030,8 @@ static struct dentry *trace_options_init_dentry(struct trace_array *tr)
 	if (tr->options)
 		return tr->options;
 
-	d_tracer = tracing_init_dentry_tr(tr);
-	if (!d_tracer)
+	d_tracer = tracing_get_dentry(tr);
+	if (IS_ERR(d_tracer))
 		return NULL;
 
 	tr->options = debugfs_create_dir("options", d_tracer);
@@ -6416,7 +6360,7 @@ static int instance_delete(const char *name)
 		goto out_unlock;
 
 	ret = -EBUSY;
-	if (tr->ref)
+	if (tr->ref || (tr->current_trace && tr->current_trace->ref))
 		goto out_unlock;
 
 	list_del(&tr->list);
@@ -6571,6 +6515,33 @@ init_tracer_debugfs(struct trace_array *tr, struct dentry *d_tracer)
 
 }
 
+/**
+ * tracing_init_dentry - initialize top level trace array
+ *
+ * This is called when creating files or directories in the tracing
+ * directory. It is called via fs_initcall() by any of the boot up code
+ * and expects to return the dentry of the top level tracing directory.
+ */
+struct dentry *tracing_init_dentry(void)
+{
+	struct trace_array *tr = &global_trace;
+
+	if (tr->dir)
+		return tr->dir;
+
+	if (WARN_ON(!debugfs_initialized()))
+		return ERR_PTR(-ENODEV);
+
+	tr->dir = debugfs_create_dir("tracing", NULL);
+
+	if (!tr->dir) {
+		pr_warn_once("Could not create debugfs directory 'tracing'\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return tr->dir;
+}
+
 static __init int tracer_init_debugfs(void)
 {
 	struct dentry *d_tracer;
@@ -6578,7 +6549,7 @@ static __init int tracer_init_debugfs(void)
 	trace_access_lock_init();
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	init_tracer_debugfs(&global_trace, d_tracer);
@@ -6811,7 +6782,6 @@ __init static int tracer_alloc_buffers(void)
 	int ring_buf_size;
 	int ret = -ENOMEM;
 
-
 	if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
 		goto out;
 
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8de48bac1ce..dd8205a3576 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -388,6 +388,7 @@ struct tracer {
 	struct tracer		*next;
 	struct tracer_flags	*flags;
 	int			enabled;
+	int			ref;
 	bool			print_max;
 	bool			allow_instances;
 #ifdef CONFIG_TRACER_MAX_TRACE
@@ -541,7 +542,6 @@ struct dentry *trace_create_file(const char *name,
 				 void *data,
 				 const struct file_operations *fops);
 
-struct dentry *tracing_init_dentry_tr(struct trace_array *tr);
 struct dentry *tracing_init_dentry(void);
 
 struct ring_buffer_event;
diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index 7d6e2afde66..57cbf1efdd4 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -7,7 +7,6 @@
 #include <linux/seq_file.h>
 #include <linux/spinlock.h>
 #include <linux/irqflags.h>
-#include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/module.h>
 #include <linux/ftrace.h>
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index b03a0ea77b9..db54dda10cc 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2531,7 +2531,7 @@ static __init int event_trace_init(void)
 		return -ENODEV;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	entry = debugfs_create_file("available_events", 0444, d_tracer,
diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c
index d4ddde28a81..12e2b99be86 100644
--- a/kernel/trace/trace_export.c
+++ b/kernel/trace/trace_export.c
@@ -6,12 +6,10 @@
 #include <linux/stringify.h>
 #include <linux/kallsyms.h>
 #include <linux/seq_file.h>
-#include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
 #include <linux/module.h>
 #include <linux/init.h>
-#include <linux/fs.h>
 
 #include "trace_output.h"
 
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index ba476009e5d..2d25ad1526b 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -1437,7 +1437,7 @@ static __init int init_graph_debugfs(void)
 	struct dentry *d_tracer;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	trace_create_file("max_graph_depth", 0644, d_tracer,
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 9bb104f748d..8523ea345f2 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -10,11 +10,9 @@
  *  Copyright (C) 2004 Nadia Yvette Chambers
  */
 #include <linux/kallsyms.h>
-#include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/module.h>
 #include <linux/ftrace.h>
-#include <linux/fs.h>
 
 #include "trace.h"
 
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 296079ae658..d73f565b4e0 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1320,7 +1320,7 @@ static __init int init_kprobe_trace(void)
 		return -EINVAL;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	entry = debugfs_create_file("kprobe_events", 0644, d_tracer,
diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c
index fcf0a9e4891..8bb2071474d 100644
--- a/kernel/trace/trace_nop.c
+++ b/kernel/trace/trace_nop.c
@@ -6,8 +6,6 @@
  */
 
 #include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/debugfs.h>
 #include <linux/ftrace.h>
 
 #include "trace.h"
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index b77b9a69761..692bf7184c8 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -177,6 +177,50 @@ ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len)
 }
 EXPORT_SYMBOL(ftrace_print_hex_seq);
 
+const char *
+ftrace_print_array_seq(struct trace_seq *p, const void *buf, int buf_len,
+		       size_t el_size)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+	const char *prefix = "";
+	void *ptr = (void *)buf;
+
+	trace_seq_putc(p, '{');
+
+	while (ptr < buf + buf_len) {
+		switch (el_size) {
+		case 1:
+			trace_seq_printf(p, "%s0x%x", prefix,
+					 *(u8 *)ptr);
+			break;
+		case 2:
+			trace_seq_printf(p, "%s0x%x", prefix,
+					 *(u16 *)ptr);
+			break;
+		case 4:
+			trace_seq_printf(p, "%s0x%x", prefix,
+					 *(u32 *)ptr);
+			break;
+		case 8:
+			trace_seq_printf(p, "%s0x%llx", prefix,
+					 *(u64 *)ptr);
+			break;
+		default:
+			trace_seq_printf(p, "BAD SIZE:%zu 0x%x", el_size,
+					 *(u8 *)ptr);
+			el_size = 1;
+		}
+		prefix = ",";
+		ptr += el_size;
+	}
+
+	trace_seq_putc(p, '}');
+	trace_seq_putc(p, 0);
+
+	return ret;
+}
+EXPORT_SYMBOL(ftrace_print_array_seq);
+
 int ftrace_raw_output_prep(struct trace_iterator *iter,
 			   struct trace_event *trace_event)
 {
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index c4e70b6bd7f..36c1455b756 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -5,7 +5,6 @@
  *
  */
 #include <linux/seq_file.h>
-#include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/kernel.h>
 #include <linux/ftrace.h>
@@ -15,7 +14,6 @@
 #include <linux/ctype.h>
 #include <linux/list.h>
 #include <linux/slab.h>
-#include <linux/fs.h>
 
 #include "trace.h"
 
@@ -349,7 +347,7 @@ static __init int init_trace_printk_function_export(void)
 	struct dentry *d_tracer;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	trace_create_file("printk_formats", 0444, d_tracer,
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index 2e293beb186..419ca37e72c 100644
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -5,8 +5,6 @@
  *
  */
 #include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/debugfs.h>
 #include <linux/kallsyms.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 8fb84b36281..d6e1003724e 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -10,8 +10,6 @@
  *  Copyright (C) 2004 Nadia Yvette Chambers
  */
 #include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/debugfs.h>
 #include <linux/kallsyms.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 16eddb308c3..c3e4fcfddd4 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -7,12 +7,10 @@
 #include <linux/seq_file.h>
 #include <linux/spinlock.h>
 #include <linux/uaccess.h>
-#include <linux/debugfs.h>
 #include <linux/ftrace.h>
 #include <linux/module.h>
 #include <linux/sysctl.h>
 #include <linux/init.h>
-#include <linux/fs.h>
 
 #include <asm/setup.h>
 
@@ -462,7 +460,7 @@ static __init int stack_trace_init(void)
 	struct dentry *d_tracer;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	trace_create_file("stack_max_size", 0644, d_tracer,
diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index 7af67360b33..75e19e86c95 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -276,7 +276,7 @@ static int tracing_stat_init(void)
 	struct dentry *d_tracing;
 
 	d_tracing = tracing_init_dentry();
-	if (!d_tracing)
+	if (IS_ERR(d_tracing))
 		return 0;
 
 	stat_dir = debugfs_create_dir("trace_stat", d_tracing);
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index b11441321e7..7dc1c8abecd 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -1321,7 +1321,7 @@ static __init int init_uprobe_trace(void)
 	struct dentry *d_tracer;
 
 	d_tracer = tracing_init_dentry();
-	if (!d_tracer)
+	if (IS_ERR(d_tracer))
 		return 0;
 
 	trace_create_file("uprobe_events", 0644, d_tracer,