Merge commit 'v3.2.9' into rt-3.2.9-rt13v3.2.9-rt13

1 files changed, 15 insertions, 0 deletions

diff --git a/fs/signalfd.c b/fs/signalfd.c
index 492465b451dd..7ae2a574cb25 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -30,6 +30,21 @@
 #include <linux/signalfd.h>
 #include <linux/syscalls.h>
 
+void signalfd_cleanup(struct sighand_struct *sighand)
+{
+	wait_queue_head_t *wqh = &sighand->signalfd_wqh;
+	/*
+	 * The lockless check can race with remove_wait_queue() in progress,
+	 * but in this case its caller should run under rcu_read_lock() and
+	 * sighand_cachep is SLAB_DESTROY_BY_RCU, we can safely return.
+	 */
+	if (likely(!waitqueue_active(wqh)))
+		return;
+
+	/* wait_queue_t->func(POLLFREE) should do remove_wait_queue() */
+	wake_up_poll(wqh, POLLHUP | POLLFREE);
+}
+
 struct signalfd_ctx {
 	sigset_t sigmask;
 };