ring-buffer: have benchmark test handle discarded events

With the addition of commit:

  cdf34b881e5533e6eabc25ba96118bdcee9ddd7a
  ring-buffer: prevent adding write in discarded area

The ring buffer may now add discarded events when a write passes
the end of a buffer page. Before, a discarded event was only added
when the tracer deliberately created one. The ring buffer benchmark
test does not handle discarded events when it reads the buffer and
fails when it encounters one.

Also fix the increment for large data entries (luckily, the test did
not add any yet).

[ Impact: fix false failure of ring buffer self test ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index 8d68e149a8b3d9eaf9ed4844b22f8f98eadbf3ff..cf6b0f50134e9b0a5e6099c8958d87c32015a53a 100644 (file)
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -102,8 +102,10 @@ static enum event_status read_page(int cpu)
                        event = (void *)&rpage->data[i];
                        switch (event->type_len) {
                        case RINGBUF_TYPE_PADDING:
-                               /* We don't expect any padding */
-                               KILL_TEST();
+                               /* failed writes may be discarded events */
+                               if (!event->time_delta)
+                                       KILL_TEST();
+                               inc = event->array[0] + 4;
                                break;
                        case RINGBUF_TYPE_TIME_EXTEND:
                                inc = 8;
@@ -119,7 +121,7 @@ static enum event_status read_page(int cpu)
                                        KILL_TEST();
                                        break;
                                }
-                               inc = event->array[0];
+                               inc = event->array[0] + 4;
                                break;
                        default:
                                entry = ring_buffer_event_data(event);