tracing: Fix code comments in trace.c

Naming in code comments for tracing_snapshot, tracing_snapshot_alloc
and trace_pid_filter_add_remove_task don't match the real function
names.  And latency_trace has been removed from tracing directory.
Fix them.

Link: http://lkml.kernel.org/r/1508394753-20887-1-git-send-email-chuhu@redhat.com

Fixes: cab50379 ("tracing/ftrace: Enable snapshot function trigger")
Fixes: 886b5b73 ("tracing: remove /debug/tracing/latency_trace")
Signed-off-by: NChunyu Hu <chuhu@redhat.com>
[ Replaced /sys/kernel/debug/tracing with /sys/kerne/tracing ]
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

kernel/trace/trace.c

@@ -362,7 +362,7 @@ trace_ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct
 }
 
 /**
- * trace_pid_filter_add_remove - Add or remove a task from a pid_list
+ * trace_pid_filter_add_remove_task - Add or remove a task from a pid_list
  * @pid_list: The list to modify
  * @self: The current task for fork or NULL for exit
  * @task: The task to add or remove
@@ -925,7 +925,7 @@ static void tracing_snapshot_instance(struct trace_array *tr)
 }
 
 /**
- * trace_snapshot - take a snapshot of the current buffer.
+ * tracing_snapshot - take a snapshot of the current buffer.
  *
  * This causes a swap between the snapshot buffer and the current live
  * tracing buffer. You can use this to take snapshots of the live
@@ -1004,9 +1004,9 @@ int tracing_alloc_snapshot(void)
 EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
 
 /**
- * trace_snapshot_alloc - allocate and take a snapshot of the current buffer.
+ * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
  *
- * This is similar to trace_snapshot(), but it will allocate the
+ * This is similar to tracing_snapshot(), but it will allocate the
  * snapshot buffer if it isn't already allocated. Use this only
  * where it is safe to sleep, as the allocation may sleep.
  *
@@ -1303,7 +1303,7 @@ unsigned long __read_mostly	tracing_thresh;
 /*
  * Copy the new maximum trace into the separate maximum-trace
  * structure. (this way the maximum trace is permanently saved,
- * for later retrieval via /sys/kernel/debug/tracing/latency_trace)
+ * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
  */
 static void
 __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)