implement O_NONBLOCK for /proc/xen/xenbus
This patch implements O_NONBLOCK for /proc/xen/xenbus. It is a simple
matter of returning -EAGAIN instead of waiting on a queue.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/drivers/xen/xenfs/xenbus.c b/drivers/xen/xenfs/xenbus.c
index a9592d9..9d5b519 100644
--- a/drivers/xen/xenfs/xenbus.c
+++ b/drivers/xen/xenfs/xenbus.c
@@ -122,6 +122,9 @@
mutex_lock(&u->reply_mutex);
while (list_empty(&u->read_buffers)) {
mutex_unlock(&u->reply_mutex);
+ if (filp->f_flags & O_NONBLOCK)
+ return -EAGAIN;
+
ret = wait_event_interruptible(u->read_waitq,
!list_empty(&u->read_buffers));
if (ret)