[PATCH] tracing: fix missing function_graph events when we splice_read from trace_pipe

[Lai Jiangshan <laijs@cn.fujitsu.com>]

About a half events are missing when we splice_read
from trace_pipe. They are consumed unexpected.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index e30e6b1..41996fc 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3085,7 +3085,8 @@ tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
 			break;
 		}
 
-		trace_consume(iter);
+		if (ret != TRACE_TYPE_NO_CONSUME)
+			trace_consume(iter);
 		rem -= count;
 		if (!find_next_entry_inc(iter))	{
 			rem = 0;
@@ -4230,8 +4231,11 @@ static void __ftrace_dump(bool disable_tracing)
 		iter.pos = -1;
 
 		if (find_next_entry_inc(&iter) != NULL) {
-			print_trace_line(&iter);
-			trace_consume(&iter);
+			int ret;
+
+			ret = print_trace_line(&iter);
+			if (ret != TRACE_TYPE_NO_CONSUME)
+				trace_consume(&iter);
 		}
 
 		trace_printk_seq(&iter.seq);