enic: support skb->xmit_more

Check and update posted_index only when skb->xmit_more is 0 or tx queue is full.

v2:
use txq_map instead of skb_get_queue_mapping(skb)

Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 17 insertions, 11 deletions

diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c
index 5afe360c7e89..b9cda2fc5ae8 100644
--- a/drivers/net/ethernet/cisco/enic/enic_main.c
+++ b/drivers/net/ethernet/cisco/enic/enic_main.c
@@ -533,6 +533,7 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff *skb,
         struct vnic_wq *wq;
         unsigned long flags;
         unsigned int txq_map;
+        struct netdev_queue *txq;
 
         if (skb->len <= 0) {
                 dev_kfree_skb_any(skb);
@@ -541,6 +542,7 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff *skb,
 
         txq_map = skb_get_queue_mapping(skb) % enic->wq_count;
         wq = &enic->wq[txq_map];
+        txq = netdev_get_tx_queue(netdev, txq_map);
 
         /* Non-TSO sends must fit within ENIC_NON_TSO_MAX_DESC descs,
          * which is very likely.  In the off chance it's going to take
@@ -558,7 +560,7 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff *skb,
 
         if (vnic_wq_desc_avail(wq) <
             skb_shinfo(skb)->nr_frags + ENIC_DESC_MAX_SPLITS) {
-                netif_tx_stop_queue(netdev_get_tx_queue(netdev, txq_map));
+                netif_tx_stop_queue(txq);
                 /* This is a hard error, log it */
                 netdev_err(netdev, "BUG! Tx ring full when queue awake!\n");
                 spin_unlock_irqrestore(&enic->wq_lock[txq_map], flags);
@@ -568,7 +570,9 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff *skb,
         enic_queue_wq_skb(enic, wq, skb);
 
         if (vnic_wq_desc_avail(wq) < MAX_SKB_FRAGS + ENIC_DESC_MAX_SPLITS)
-                netif_tx_stop_queue(netdev_get_tx_queue(netdev, txq_map));
+                netif_tx_stop_queue(txq);
+        if (!skb->xmit_more || netif_xmit_stopped(txq))
+                vnic_wq_doorbell(wq);
 
         spin_unlock_irqrestore(&enic->wq_lock[txq_map], flags);
 
diff --git a/drivers/net/ethernet/cisco/enic/vnic_wq.h b/drivers/net/ethernet/cisco/enic/vnic_wq.h
index 2c6c70804a39..816f1ad6072f 100644
--- a/drivers/net/ethernet/cisco/enic/vnic_wq.h
+++ b/drivers/net/ethernet/cisco/enic/vnic_wq.h
@@ -104,6 +104,17 @@ static inline void *vnic_wq_next_desc(struct vnic_wq *wq)
         return wq->to_use->desc;
 }
 
+static inline void vnic_wq_doorbell(struct vnic_wq *wq)
+{
+        /* Adding write memory barrier prevents compiler and/or CPU
+         * reordering, thus avoiding descriptor posting before
+         * descriptor is initialized. Otherwise, hardware can read
+         * stale descriptor fields.
+         */
+        wmb();
+        iowrite32(wq->to_use->index, &wq->ctrl->posted_index);
+}
+
 static inline void vnic_wq_post(struct vnic_wq *wq,
         void *os_buf, dma_addr_t dma_addr,
         unsigned int len, int sop, int eop,
@@ -122,15 +133,6 @@ static inline void vnic_wq_post(struct vnic_wq *wq,
         buf->wr_id = wrid;
 
         buf = buf->next;
-        if (eop) {
-                /* Adding write memory barrier prevents compiler and/or CPU
-                 * reordering, thus avoiding descriptor posting before
-                 * descriptor is initialized. Otherwise, hardware can read
-                 * stale descriptor fields.
-                 */
-                wmb();
-                iowrite32(buf->index, &wq->ctrl->posted_index);
-        }
         wq->to_use = buf;
 
         wq->ring.desc_avail -= desc_skip_cnt;