net/mlx4_en: using non collapsed CQ on TX

Moving to regular Completion Queue implementation (not collapsed)
Completion for each transmitted packet is written to new entry.

Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_cq.c b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
index 227997d..2d1a342 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_cq.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_cq.c
@@ -51,10 +51,7 @@ int mlx4_en_create_cq(struct mlx4_en_priv *priv,
        int err;
 
        cq->size = entries;
-       if (mode == RX)
-               cq->buf_size = cq->size * sizeof(struct mlx4_cqe);
-       else
-               cq->buf_size = sizeof(struct mlx4_cqe);
+       cq->buf_size = cq->size * sizeof(struct mlx4_cqe);
 
        cq->ring = ring;
        cq->is_tx = mode;
@@ -120,7 +117,7 @@ int mlx4_en_activate_cq(struct mlx4_en_priv *priv, struct mlx4_en_cq *cq,
                cq->size = priv->rx_ring[cq->ring].actual_size;
 
        err = mlx4_cq_alloc(mdev->dev, cq->size, &cq->wqres.mtt, &mdev->priv_uar,
-                           cq->wqres.db.dma, &cq->mcq, cq->vector, cq->is_tx);
+                           cq->wqres.db.dma, &cq->mcq, cq->vector, 0);
        if (err)
                return err;
 

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_tx.c b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
index d901b42..3094f94 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx4/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_tx.c
@@ -307,59 +307,60 @@ int mlx4_en_free_tx_buf(struct net_device *dev, struct mlx4_en_tx_ring *ring)
        return cnt;
 }
 
-
 static void mlx4_en_process_tx_cq(struct net_device *dev, struct mlx4_en_cq *cq)
 {
        struct mlx4_en_priv *priv = netdev_priv(dev);
        struct mlx4_cq *mcq = &cq->mcq;
        struct mlx4_en_tx_ring *ring = &priv->tx_ring[cq->ring];
-       struct mlx4_cqe *cqe = cq->buf;
+       struct mlx4_cqe *cqe;
        u16 index;
-       u16 new_index;
+       u16 new_index, ring_index;
        u32 txbbs_skipped = 0;
-       u32 cq_last_sav;
-
-       /* index always points to the first TXBB of the last polled descriptor */
-       index = ring->cons & ring->size_mask;
-       new_index = be16_to_cpu(cqe->wqe_index) & ring->size_mask;
-       if (index == new_index)
-               return;
+       u32 cons_index = mcq->cons_index;
+       int size = cq->size;
+       u32 size_mask = ring->size_mask;
+       struct mlx4_cqe *buf = cq->buf;
 
        if (!priv->port_up)
                return;
 
-       /*
-        * We use a two-stage loop:
-        * - the first samples the HW-updated CQE
-        * - the second frees TXBBs until the last sample
-        * This lets us amortize CQE cache misses, while still polling the CQ
-        * until is quiescent.
-        */
-       cq_last_sav = mcq->cons_index;
-       do {
+       index = cons_index & size_mask;
+       cqe = &buf[index];
+       ring_index = ring->cons & size_mask;
+
+       /* Process all completed CQEs */
+       while (XNOR(cqe->owner_sr_opcode & MLX4_CQE_OWNER_MASK,
+                       cons_index & size)) {
+               /*
+                * make sure we read the CQE after we read the
+                * ownership bit
+                */
+               rmb();
+
+               /* Skip over last polled CQE */
+               new_index = be16_to_cpu(cqe->wqe_index) & size_mask;
+
                do {
-                       /* Skip over last polled CQE */
-                       index = (index + ring->last_nr_txbb) & ring->size_mask;
                        txbbs_skipped += ring->last_nr_txbb;
-
-                       /* Poll next CQE */
+                       ring_index = (ring_index + ring->last_nr_txbb) & size_mask;
+                       /* free next descriptor */
                        ring->last_nr_txbb = mlx4_en_free_tx_desc(
-                                               priv, ring, index,
-                                               !!((ring->cons + txbbs_skipped) &
-                                                  ring->size));
-                       ++mcq->cons_index;
-
-               } while (index != new_index);
+                                       priv, ring, ring_index,
+                                       !!((ring->cons + txbbs_skipped) &
+                                                       ring->size));
+               } while (ring_index != new_index);
+
+               ++cons_index;
+               index = cons_index & size_mask;
+               cqe = &buf[index];
+       }
 
-               new_index = be16_to_cpu(cqe->wqe_index) & ring->size_mask;
-       } while (index != new_index);
-       AVG_PERF_COUNTER(priv->pstats.tx_coal_avg,
-                        (u32) (mcq->cons_index - cq_last_sav));
 
        /*
         * To prevent CQ overflow we first update CQ consumer and only then
         * the ring consumer.
         */
+       mcq->cons_index = cons_index;
        mlx4_cq_set_ci(mcq);
        wmb();
        ring->cons += txbbs_skipped;