2 files changed, 16 insertions, 17 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 6dc76c1e807b..a7bf74727116 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -200,11 +200,6 @@ struct xenvif_queue { /* Per-queue data for xenvif */
 	struct xenvif_stats stats;
 };
 
-/* Maximum number of Rx slots a to-guest packet may use, including the
- * slot needed for GSO meta-data.
- */
-#define XEN_NETBK_RX_SLOTS_MAX (MAX_SKB_FRAGS + 1)
-
 enum state_bit_shift {
 	/* This bit marks that the vif is connected */
 	VIF_STATUS_CONNECTED,
@@ -317,11 +312,6 @@ int xenvif_dealloc_kthread(void *data);
 
 void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb);
 
-/* Determine whether the needed number of slots (req) are available,
- * and set req_event if not.
- */
-bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed);
-
 void xenvif_carrier_on(struct xenvif *vif);
 
 /* Callback from stack when TX packet can be released */
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 42569b994ea8..b588b1a08cd4 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -149,9 +149,20 @@ static inline pending_ring_idx_t pending_index(unsigned i)
 	return i & (MAX_PENDING_REQS-1);
 }
 
-bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue, int needed)
+static int xenvif_rx_ring_slots_needed(struct xenvif *vif)
+{
+	if (vif->gso_mask)
+		return DIV_ROUND_UP(vif->dev->gso_max_size, PAGE_SIZE) + 1;
+	else
+		return DIV_ROUND_UP(vif->dev->mtu, PAGE_SIZE);
+}
+
+static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
 {
 	RING_IDX prod, cons;
+	int needed;
+
+	needed = xenvif_rx_ring_slots_needed(queue->vif);
 
 	do {
 		prod = queue->rx.sring->req_prod;
@@ -513,7 +524,7 @@ static void xenvif_rx_action(struct xenvif_queue *queue)
 
 	skb_queue_head_init(&rxq);
 
-	while (xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX)
+	while (xenvif_rx_ring_slots_available(queue)
 	       && (skb = xenvif_rx_dequeue(queue)) != NULL) {
 		queue->last_rx_time = jiffies;
 
@@ -1938,8 +1949,7 @@ static bool xenvif_rx_queue_stalled(struct xenvif_queue *queue)
 	prod = queue->rx.sring->req_prod;
 	cons = queue->rx.req_cons;
 
-	return !queue->stalled
-		&& prod - cons < XEN_NETBK_RX_SLOTS_MAX
+	return !queue->stalled && prod - cons < 1
 		&& time_after(jiffies,
 			      queue->last_rx_time + queue->vif->stall_timeout);
 }
@@ -1951,14 +1961,13 @@ static bool xenvif_rx_queue_ready(struct xenvif_queue *queue)
 	prod = queue->rx.sring->req_prod;
 	cons = queue->rx.req_cons;
 
-	return queue->stalled
-		&& prod - cons >= XEN_NETBK_RX_SLOTS_MAX;
+	return queue->stalled && prod - cons >= 1;
 }
 
 static bool xenvif_have_rx_work(struct xenvif_queue *queue)
 {
 	return (!skb_queue_empty(&queue->rx_queue)
-		&& xenvif_rx_ring_slots_available(queue, XEN_NETBK_RX_SLOTS_MAX))
+		&& xenvif_rx_ring_slots_available(queue))
 		|| (queue->vif->stall_timeout &&
 		    (xenvif_rx_queue_stalled(queue)
 		     || xenvif_rx_queue_ready(queue)))