[PATCH net-next 6/9] ep93xx_eth: add GRO support

[Eric Dumazet]

Use napi_complete_done() instead of __napi_complete() to :

1) Get support of gro_flush_timeout if opt-in
2) Not rearm interrupts for busy-polling users.
3) use standard NAPI API.
4) get rid of baroque code and ease maintenance.

In particular, this driver used napi_reschedule() in
a way that would defeat NAPI poll budget control and
would lead to potential infinite loop.

Signed-off-by: Eric Dumazet <eduma...@google.com>
---
 drivers/net/ethernet/cirrus/ep93xx_eth.c | 24 +++---------------------
 1 file changed, 3 insertions(+), 21 deletions(-)

diff --git a/drivers/net/ethernet/cirrus/ep93xx_eth.c 
b/drivers/net/ethernet/cirrus/ep93xx_eth.c
index 
396c88678eabfec556536ca4a81f86224563..bb34a3d0ea446256bd025b006b201581c257 
100644
--- a/drivers/net/ethernet/cirrus/ep93xx_eth.c
+++ b/drivers/net/ethernet/cirrus/ep93xx_eth.c
@@ -294,7 +294,7 @@ static int ep93xx_rx(struct net_device *dev, int processed, 
int budget)
                        skb_put(skb, length);
                        skb->protocol = eth_type_trans(skb, dev);
 
-                       netif_receive_skb(skb);
+                       napi_gro_receive(&ep->napi, skb);
 
                        dev->stats.rx_packets++;
                        dev->stats.rx_bytes += length;
@@ -310,35 +310,17 @@ static int ep93xx_rx(struct net_device *dev, int 
processed, int budget)
        return processed;
 }
 
-static int ep93xx_have_more_rx(struct ep93xx_priv *ep)
-{
-       struct ep93xx_rstat *rstat = ep->descs->rstat + ep->rx_pointer;
-       return !!((rstat->rstat0 & RSTAT0_RFP) && (rstat->rstat1 & RSTAT1_RFP));
-}
-
 static int ep93xx_poll(struct napi_struct *napi, int budget)
 {
        struct ep93xx_priv *ep = container_of(napi, struct ep93xx_priv, napi);
        struct net_device *dev = ep->dev;
-       int rx = 0;
+       int rx;
 
-poll_some_more:
        rx = ep93xx_rx(dev, rx, budget);
-       if (rx < budget) {
-               int more = 0;
-
+       if ((rx < budget) && napi_complete_done(napi, rx)) {
                spin_lock_irq(&ep->rx_lock);
-               __napi_complete(napi);
                wrl(ep, REG_INTEN, REG_INTEN_TX | REG_INTEN_RX);
-               if (ep93xx_have_more_rx(ep)) {
-                       wrl(ep, REG_INTEN, REG_INTEN_TX);
-                       wrl(ep, REG_INTSTSP, REG_INTSTS_RX);
-                       more = 1;
-               }
                spin_unlock_irq(&ep->rx_lock);
-
-               if (more && napi_reschedule(napi))
-                       goto poll_some_more;
        }
 
        if (rx) {
-- 
2.11.0.483.g087da7b7c-goog