[net-next PATCH V2 2/3] mlx4: use napi_consume_skb API to get bulk free operations

[Jesper Dangaard Brouer]

Bulk free of SKBs happen transparently by the API call napi_consume_skb().
The napi budget parameter is usually needed by napi_consume_skb()
to detect if called from netpoll.  In this patch it have an extra meaning.

For mlx4 driver, the mlx4_en_stop_port() call is done outside
NAPI/softirq context, and cleanup the entire TX ring via
mlx4_en_free_tx_buf().  The code mlx4_en_free_tx_desc() for
freeing SKBs are shared with NAPI calls.

To handle this shared use the zero budget indication is reused,
and handled appropiately in napi_consume_skb(). To reflect this,
variable is called napi_mode for the function call that needed
this distinction.

Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_tx.c |   16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c 
b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index e0946ab22010..1b41feafce9e 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -276,7 +276,8 @@ static void mlx4_en_stamp_wqe(struct mlx4_en_priv *priv,
 
 static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
                                struct mlx4_en_tx_ring *ring,
-                               int index, u8 owner, u64 timestamp)
+                               int index, u8 owner, u64 timestamp,
+                               int napi_mode)
 {
        struct mlx4_en_tx_info *tx_info = &ring->tx_info[index];
        struct mlx4_en_tx_desc *tx_desc = ring->buf + index * TXBB_SIZE;
@@ -347,7 +348,8 @@ static u32 mlx4_en_free_tx_desc(struct mlx4_en_priv *priv,
                        }
                }
        }
-       dev_consume_skb_any(skb);
+       napi_consume_skb(skb, napi_mode);
+
        return tx_info->nr_txbb;
 }
 
@@ -371,7 +373,9 @@ int mlx4_en_free_tx_buf(struct net_device *dev, struct 
mlx4_en_tx_ring *ring)
        while (ring->cons != ring->prod) {
                ring->last_nr_txbb = mlx4_en_free_tx_desc(priv, ring,
                                                ring->cons & ring->size_mask,
-                                               !!(ring->cons & ring->size), 0);
+                                               !!(ring->cons & ring->size), 0,
+                                               0 /* none-NAPI caller */
+                       );
                ring->cons += ring->last_nr_txbb;
                cnt++;
        }
@@ -385,7 +389,7 @@ int mlx4_en_free_tx_buf(struct net_device *dev, struct 
mlx4_en_tx_ring *ring)
 }
 
 static bool mlx4_en_process_tx_cq(struct net_device *dev,
-                                struct mlx4_en_cq *cq)
+                                 struct mlx4_en_cq *cq, int napi_budget)
 {
        struct mlx4_en_priv *priv = netdev_priv(dev);
        struct mlx4_cq *mcq = &cq->mcq;
@@ -451,7 +455,7 @@ static bool mlx4_en_process_tx_cq(struct net_device *dev,
                        last_nr_txbb = mlx4_en_free_tx_desc(
                                        priv, ring, ring_index,
                                        !!((ring_cons + txbbs_skipped) &
-                                       ring->size), timestamp);
+                                       ring->size), timestamp, napi_budget);
 
                        mlx4_en_stamp_wqe(priv, ring, stamp_index,
                                          !!((ring_cons + txbbs_stamp) &
@@ -511,7 +515,7 @@ int mlx4_en_poll_tx_cq(struct napi_struct *napi, int budget)
        struct mlx4_en_priv *priv = netdev_priv(dev);
        int clean_complete;
 
-       clean_complete = mlx4_en_process_tx_cq(dev, cq);
+       clean_complete = mlx4_en_process_tx_cq(dev, cq, budget);
        if (!clean_complete)
                return budget;