tracing: Clear parser->idx if only spaces are read

If only spaces were read while parsing the next string, then parser->idx should be
cleared in order to make trace_parser_loaded() return false.

Link: http://lkml.kernel.org/r/[email protected]

Acked-by: Namhyung Kim <[email protected]>
Signed-off-by: Changbin Du <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>

Author: Changbin Du

kernel/trace/trace.c

@@ -1236,14 +1236,14 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
 			cnt--;
 		}
 
+		parser->idx = 0;
+
 		/* only spaces were written */
 		if (isspace(ch) || !ch) {
 			*ppos += read;
 			ret = read;
 			goto out;
 		}
-
-		parser->idx = 0;
 	}
 
 	/* read the non-space input */