tracing: make trace pipe recognize latency format flag

The trace_pipe did not recognize the latency format flag and would produce
different output than the trace file. The problem was partly due that
the trace flags in the iterator was not set as well as the trace_pipe
zeros out part of the iterator (including the flags) to be able to use
the same routines as the trace file. trace_flags of the iterator should
not cause any problems when not zeroed out by for trace_pipe.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index bbf40f6..5c093ff 100644 (file)
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -51,6 +51,7 @@ struct trace_iterator {
        int                     cpu_file;
        struct mutex            mutex;
        struct ring_buffer_iter *buffer_iter[NR_CPUS];
+       unsigned long           iter_flags;
 
        /* The below is zeroed out in pipe_read */
        struct trace_seq        seq;
@@ -58,7 +59,6 @@ struct trace_iterator {
        int                     cpu;
        u64                     ts;
 
-       unsigned long           iter_flags;
        loff_t                  pos;
        long                    idx;
 

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index a3a8a87..cae34c6 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2826,6 +2826,9 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
        /* trace pipe does not show start of buffer */
        cpumask_setall(iter->started);
 
+       if (trace_flags & TRACE_ITER_LATENCY_FMT)
+               iter->iter_flags |= TRACE_FILE_LAT_FMT;
+
        iter->cpu_file = cpu_file;
        iter->tr = &global_trace;
        mutex_init(&iter->mutex);