[tip:perf/urgent] perf: Fix SIGIO handling

[tip-bot for Peter Zijlstra <a.p.zijlstra@chello.nl>]

Commit-ID:  f506b3dc0ec454a16d40cab9ee5d75435b39dc50
Gitweb:     http://git.kernel.org/tip/f506b3dc0ec454a16d40cab9ee5d75435b39dc50
Author:     Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Thu, 26 May 2011 17:02:53 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Sat, 28 May 2011 17:04:59 +0200

perf: Fix SIGIO handling

Vince noticed that unless we mmap() a buffer, SIGIO gets lost. So
explicitly push the wakeup (including signals) when requested.

Reported-by: Vince Weaver <vweaver1@eecs.utk.edu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Link: http://lkml.kernel.org/n/tip-2euus3f3x3dyvdk52cjxw8zu@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 kernel/events/core.c |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index c09767f..d863b3c 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5028,6 +5028,14 @@ static int __perf_event_overflow(struct perf_event *event, int nmi,
 	else
 		perf_event_output(event, nmi, data, regs);
 
+	if (event->fasync && event->pending_kill) {
+		if (nmi) {
+			event->pending_wakeup = 1;
+			irq_work_queue(&event->pending);
+		} else
+			perf_event_wakeup(event);
+	}
+
 	return ret;
 }