libceph: kill ceph_osdc_create_event() "one_shot" parameter

There is only one caller of ceph_osdc_create_event(), and it
provides 0 as its "one_shot" argument.  Get rid of that argument and
just use 0 in its place.

Replace the code in handle_watch_notify() that executes if one_shot
is nonzero in the event with a BUG_ON() call.

While modifying "osd_client.c", give handle_watch_notify() static
scope.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

drivers/block/rbd.c

@@ -1744,7 +1744,7 @@ static int rbd_dev_header_watch_sync(struct rbd_device *rbd_dev, int start)
 	rbd_assert(start ^ !!rbd_dev->watch_request);
 
 	if (start) {
-		ret = ceph_osdc_create_event(osdc, rbd_watch_cb, 0, rbd_dev,
+		ret = ceph_osdc_create_event(osdc, rbd_watch_cb, rbd_dev,
 						&rbd_dev->watch_event);
 		if (ret < 0)
 			return ret;

include/linux/ceph/osd_client.h

@@ -273,8 +273,7 @@ extern int ceph_osdc_writepages(struct ceph_osd_client *osdc,
 /* watch/notify events */
 extern int ceph_osdc_create_event(struct ceph_osd_client *osdc,
 				  void (*event_cb)(u64, u64, u8, void *),
-				  int one_shot, void *data,
-				  struct ceph_osd_event **pevent);
+				  void *data, struct ceph_osd_event **pevent);
 extern void ceph_osdc_cancel_event(struct ceph_osd_event *event);
 extern int ceph_osdc_wait_event(struct ceph_osd_event *event,
 				unsigned long timeout);

net/ceph/osd_client.c

@@ -1477,8 +1477,7 @@ static void __remove_event(struct ceph_osd_event *event)
 
 int ceph_osdc_create_event(struct ceph_osd_client *osdc,
 			   void (*event_cb)(u64, u64, u8, void *),
-			   int one_shot, void *data,
-			   struct ceph_osd_event **pevent)
+			   void *data, struct ceph_osd_event **pevent)
 {
 	struct ceph_osd_event *event;
 
@@ -1488,7 +1487,7 @@ int ceph_osdc_create_event(struct ceph_osd_client *osdc,
 
 	dout("create_event %p\n", event);
 	event->cb = event_cb;
-	event->one_shot = one_shot;
+	event->one_shot = 0;
 	event->data = data;
 	event->osdc = osdc;
 	INIT_LIST_HEAD(&event->osd_node);
@@ -1541,7 +1540,8 @@ static void do_event_work(struct work_struct *work)
 /*
  * Process osd watch notifications
  */
-void handle_watch_notify(struct ceph_osd_client *osdc, struct ceph_msg *msg)
+static void handle_watch_notify(struct ceph_osd_client *osdc,
+				struct ceph_msg *msg)
 {
 	void *p, *end;
 	u8 proto_ver;
@@ -1562,9 +1562,8 @@ void handle_watch_notify(struct ceph_osd_client *osdc, struct ceph_msg *msg)
 	spin_lock(&osdc->event_lock);
 	event = __find_event(osdc, cookie);
 	if (event) {
+		BUG_ON(event->one_shot);
 		get_event(event);
-		if (event->one_shot)
-			__remove_event(event);
 	}
 	spin_unlock(&osdc->event_lock);
 	dout("handle_watch_notify cookie %lld ver %lld event %p\n",