net: remove skb recycling

Over time, skb recycling infrastructure got litle interest and
many bugs. Generic rx path skb allocation is now using page
fragments for efficient GRO / TCP coalescing, and recyling
a tx skb for rx path is not worth the pain.

Last identified bug is that fat skbs can be recycled
and it can endup using high order pages after few iterations.

With help from Maxime Bizon, who pointed out that commit
87151b8689d (net: allow pskb_expand_head() to get maximum tailroom)
introduced this regression for recycled skbs.

Instead of fixing this bug, lets remove skb recycling.

Drivers wanting really hot skbs should use build_skb() anyway,
to allocate/populate sk_buff right before netif_receive_skb()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 16 deletions

diff --git a/drivers/net/ethernet/marvell/mv643xx_eth.c b/drivers/net/ethernet/marvell/mv643xx_eth.c
index 087b9e0669f1..84c13263c514 100644
--- a/drivers/net/ethernet/marvell/mv643xx_eth.c
+++ b/drivers/net/ethernet/marvell/mv643xx_eth.c
@@ -412,7 +412,6 @@ struct mv643xx_eth_private {
         u8 work_rx_refill;
 
         int skb_size;
-        struct sk_buff_head rx_recycle;
 
         /*
          * RX state.
@@ -673,9 +672,7 @@ static int rxq_refill(struct rx_queue *rxq, int budget)
                 struct rx_desc *rx_desc;
                 int size;
 
-                skb = __skb_dequeue(&mp->rx_recycle);
-                if (skb == NULL)
-                        skb = netdev_alloc_skb(mp->dev, mp->skb_size);
+                skb = netdev_alloc_skb(mp->dev, mp->skb_size);
 
                 if (skb == NULL) {
                         mp->oom = 1;
@@ -989,14 +986,7 @@ static int txq_reclaim(struct tx_queue *txq, int budget, int force)
                                        desc->byte_cnt, DMA_TO_DEVICE);
                 }
 
-                if (skb != NULL) {
-                        if (skb_queue_len(&mp->rx_recycle) <
-                                        mp->rx_ring_size &&
-                            skb_recycle_check(skb, mp->skb_size))
-                                __skb_queue_head(&mp->rx_recycle, skb);
-                        else
-                                dev_kfree_skb(skb);
-                }
+                dev_kfree_skb(skb);
         }
 
         __netif_tx_unlock(nq);
@@ -2349,8 +2339,6 @@ static int mv643xx_eth_open(struct net_device *dev)
 
         napi_enable(&mp->napi);
 
-        skb_queue_head_init(&mp->rx_recycle);
-
         mp->int_mask = INT_EXT;
 
         for (i = 0; i < mp->rxq_count; i++) {
@@ -2445,8 +2433,6 @@ static int mv643xx_eth_stop(struct net_device *dev)
         mib_counters_update(mp);
         del_timer_sync(&mp->mib_counters_timer);
 
-        skb_queue_purge(&mp->rx_recycle);
-
         for (i = 0; i < mp->rxq_count; i++)
                 rxq_deinit(mp->rxq + i);
         for (i = 0; i < mp->txq_count; i++)