Commit 2dc8f095 authored May 12, 2008 by Steven Rostedt Committed by Thomas Gleixner May 23, 2008

ftrace: trace_pipe implement NONBLOCK



This patch implements "NONBLOCK" for trace_pipe. If the trace_pipe is opened
with O_NONBLOCK, then the trace_pipe read will not block when buffer is empty.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

parent 84527997

kernel/trace/trace.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -2233,6 +2233,10 @@ tracing_read_pipe(struct file filp, char __user ubuf,
		start = 0;

		while (trace_empty(iter)) {

		if ((filp->f_flags & O_NONBLOCK))
		return -EAGAIN;

		/*
		* This is a make-shift waitqueue. The reason we don't use
		* an actual wait queue is because: