mlx4_en: Remove redundant refill code on RX

Our RX rings are always full, there is no need to check whether
we need to fill them or not. If we fail to allocate a new socket
buffer, the incoming packet is dropped an the ring remains full.
Signed-off-by: NYevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/mlx4/en_netdev.c

@@ -881,7 +881,6 @@ void mlx4_en_destroy_netdev(struct net_device *dev)
 		mlx4_free_hwq_res(mdev->dev, &priv->res, MLX4_EN_PAGE_SIZE);
 
 	cancel_delayed_work(&priv->stats_task);
-	cancel_delayed_work(&priv->refill_task);
 	/* flush any pending task for this netdev */
 	flush_workqueue(mdev->workqueue);
 
@@ -986,7 +985,6 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
 	spin_lock_init(&priv->stats_lock);
 	INIT_WORK(&priv->mcast_task, mlx4_en_do_set_multicast);
 	INIT_WORK(&priv->mac_task, mlx4_en_do_set_mac);
-	INIT_DELAYED_WORK(&priv->refill_task, mlx4_en_rx_refill);
 	INIT_WORK(&priv->watchdog_task, mlx4_en_restart);
 	INIT_WORK(&priv->linkstate_task, mlx4_en_linkstate);
 	INIT_DELAYED_WORK(&priv->stats_task, mlx4_en_do_get_stats);

drivers/net/mlx4/en_rx.c

@@ -269,31 +269,6 @@ static int mlx4_en_fill_rx_buffers(struct mlx4_en_priv *priv)
 	return 0;
 }
 
-static int mlx4_en_fill_rx_buf(struct net_device *dev,
-			       struct mlx4_en_rx_ring *ring)
-{
-	struct mlx4_en_priv *priv = netdev_priv(dev);
-	int num = 0;
-	int err;
-
-	while ((u32) (ring->prod - ring->cons) < ring->actual_size) {
-		err = mlx4_en_prepare_rx_desc(priv, ring, ring->prod &
-					      ring->size_mask);
-		if (err) {
-			if (netif_msg_rx_err(priv))
-				en_warn(priv, "Failed preparing rx descriptor\n");
-			priv->port_stats.rx_alloc_failed++;
-			break;
-		}
-		++num;
-		++ring->prod;
-	}
-	if ((u32) (ring->prod - ring->cons) == ring->actual_size)
-		ring->full = 1;
-
-	return num;
-}
-
 static void mlx4_en_free_rx_buf(struct mlx4_en_priv *priv,
 				struct mlx4_en_rx_ring *ring)
 {
@@ -312,42 +287,6 @@ static void mlx4_en_free_rx_buf(struct mlx4_en_priv *priv,
 	}
 }
 
-
-void mlx4_en_rx_refill(struct work_struct *work)
-{
-	struct delayed_work *delay = to_delayed_work(work);
-	struct mlx4_en_priv *priv = container_of(delay, struct mlx4_en_priv,
-						 refill_task);
-	struct mlx4_en_dev *mdev = priv->mdev;
-	struct net_device *dev = priv->dev;
-	struct mlx4_en_rx_ring *ring;
-	int need_refill = 0;
-	int i;
-
-	mutex_lock(&mdev->state_lock);
-	if (!mdev->device_up || !priv->port_up)
-		goto out;
-
-	/* We only get here if there are no receive buffers, so we can't race
-	 * with Rx interrupts while filling buffers */
-	for (i = 0; i < priv->rx_ring_num; i++) {
-		ring = &priv->rx_ring[i];
-		if (ring->need_refill) {
-			if (mlx4_en_fill_rx_buf(dev, ring)) {
-				ring->need_refill = 0;
-				mlx4_en_update_rx_prod_db(ring);
-			} else
-				need_refill = 1;
-		}
-	}
-	if (need_refill)
-		queue_delayed_work(mdev->workqueue, &priv->refill_task, HZ);
-
-out:
-	mutex_unlock(&mdev->state_lock);
-}
-
-
 int mlx4_en_create_rx_ring(struct mlx4_en_priv *priv,
 			   struct mlx4_en_rx_ring *ring, u32 size, u16 stride)
 {
@@ -457,9 +396,6 @@ int mlx4_en_activate_rx_rings(struct mlx4_en_priv *priv)
 			ring_ind--;
 			goto err_allocator;
 		}
-
-		/* Fill Rx buffers */
-		ring->full = 0;
 	}
 	err = mlx4_en_fill_rx_buffers(priv);
 	if (err)
@@ -647,33 +583,6 @@ static struct sk_buff *mlx4_en_rx_skb(struct mlx4_en_priv *priv,
 	return skb;
 }
 
-static void mlx4_en_copy_desc(struct mlx4_en_priv *priv,
-			      struct mlx4_en_rx_ring *ring,
-			      int from, int to, int num)
-{
-	struct skb_frag_struct *skb_frags_from;
-	struct skb_frag_struct *skb_frags_to;
-	struct mlx4_en_rx_desc *rx_desc_from;
-	struct mlx4_en_rx_desc *rx_desc_to;
-	int from_index, to_index;
-	int nr, i;
-
-	for (i = 0; i < num; i++) {
-		from_index = (from + i) & ring->size_mask;
-		to_index = (to + i) & ring->size_mask;
-		skb_frags_from = ring->rx_info + (from_index << priv->log_rx_info);
-		skb_frags_to = ring->rx_info + (to_index << priv->log_rx_info);
-		rx_desc_from = ring->buf + (from_index << ring->log_stride);
-		rx_desc_to = ring->buf + (to_index << ring->log_stride);
-
-		for (nr = 0; nr < priv->num_frags; nr++) {
-			skb_frags_to[nr].page = skb_frags_from[nr].page;
-			skb_frags_to[nr].page_offset = skb_frags_from[nr].page_offset;
-			rx_desc_to->data[nr].addr = rx_desc_from->data[nr].addr;
-		}
-	}
-}
-
 
 int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int budget)
 {
@@ -821,11 +730,6 @@ int mlx4_en_process_rx_cq(struct net_device *dev, struct mlx4_en_cq *cq, int bud
 	wmb(); /* ensure HW sees CQ consumer before we post new buffers */
 	ring->cons = cq->mcq.cons_index;
 	ring->prod += polled; /* Polled descriptors were realocated in place */
-	if (unlikely(!ring->full)) {
-		mlx4_en_copy_desc(priv, ring, ring->cons - polled,
-				  ring->prod - polled, polled);
-		mlx4_en_fill_rx_buf(dev, ring);
-	}
 	mlx4_en_update_rx_prod_db(ring);
 	return polled;
 }

drivers/net/mlx4/mlx4_en.h

@@ -295,8 +295,6 @@ struct mlx4_en_rx_ring {
 	u32 prod;
 	u32 cons;
 	u32 buf_size;
-	int need_refill;
-	int full;
 	void *buf;
 	void *rx_info;
 	unsigned long bytes;
@@ -494,7 +492,6 @@ struct mlx4_en_priv {
 	struct mlx4_en_cq rx_cq[MAX_RX_RINGS];
 	struct work_struct mcast_task;
 	struct work_struct mac_task;
-	struct delayed_work refill_task;
 	struct work_struct watchdog_task;
 	struct work_struct linkstate_task;
 	struct delayed_work stats_task;
@@ -564,7 +561,6 @@ void mlx4_en_set_default_rss_map(struct mlx4_en_priv *priv,
 int mlx4_en_config_rss_steer(struct mlx4_en_priv *priv);
 void mlx4_en_release_rss_steer(struct mlx4_en_priv *priv);
 int mlx4_en_free_tx_buf(struct net_device *dev, struct mlx4_en_tx_ring *ring);
-void mlx4_en_rx_refill(struct work_struct *work);
 void mlx4_en_rx_irq(struct mlx4_cq *mcq);
 
 int mlx4_SET_MCAST_FLTR(struct mlx4_dev *dev, u8 port, u64 mac, u64 clear, u8 mode);