net/xen-netback: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Paul Durrant <paul.durrant@citrix.com>
Cc: xen-devel@lists.xenproject.org
Cc: netdev@vger.kernel.org
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/xen-netback/common.h

@@ -307,7 +307,7 @@ static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
 	return to_xenbus_device(vif->dev->dev.parent);
 }
 
-void xenvif_tx_credit_callback(unsigned long data);
+void xenvif_tx_credit_callback(struct timer_list *t);
 
 struct xenvif *xenvif_alloc(struct device *parent,
 			    domid_t domid,

drivers/net/xen-netback/interface.c

@@ -520,7 +520,7 @@ int xenvif_init_queue(struct xenvif_queue *queue)
 
 	queue->credit_bytes = queue->remaining_credit = ~0UL;
 	queue->credit_usec  = 0UL;
-	setup_timer(&queue->credit_timeout, xenvif_tx_credit_callback, 0UL);
+	timer_setup(&queue->credit_timeout, xenvif_tx_credit_callback, 0);
 	queue->credit_window_start = get_jiffies_64();
 
 	queue->rx_queue_max = XENVIF_RX_QUEUE_BYTES;

drivers/net/xen-netback/netback.c

@@ -183,9 +183,9 @@ static void tx_add_credit(struct xenvif_queue *queue)
 	queue->rate_limited = false;
 }
 
-void xenvif_tx_credit_callback(unsigned long data)
+void xenvif_tx_credit_callback(struct timer_list *t)
 {
-	struct xenvif_queue *queue = (struct xenvif_queue *)data;
+	struct xenvif_queue *queue = from_timer(queue, t, credit_timeout);
 	tx_add_credit(queue);
 	xenvif_napi_schedule_or_enable_events(queue);
 }
@@ -700,8 +700,6 @@ static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size)
 
 	/* Still too big to send right now? Set a callback. */
 	if (size > queue->remaining_credit) {
-		queue->credit_timeout.data     =
-			(unsigned long)queue;
 		mod_timer(&queue->credit_timeout,
 			  next_credit);
 		queue->credit_window_start = next_credit;