sfc: get rid of custom busy polling code

In linux-4.5, busy polling was implemented in core
NAPI stack, meaning that all custom implementation can
be removed from drivers.

Not only we remove lot's of tricky code, we also remove
one lock operation in fast path.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Edward Cree <ecree@solarflare.com>
Cc: Bert Kenward <bkenward@solarflare.com>
Acked-by: Bert Kenward <bkenward@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 0 insertions, 42 deletions

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 466c02805f72..fcd4eeecfef4 100644
--- a/drivers/net/ethernet/sfc/efx.c
+++ b/drivers/net/ethernet/sfc/efx.c
@@ -308,9 +308,6 @@ static int efx_poll(struct napi_struct *napi, int budget)
 	struct efx_nic *efx = channel->efx;
 	int spent;
 
-	if (!efx_channel_lock_napi(channel))
-		return budget;
-
 	netif_vdbg(efx, intr, efx->net_dev,
 		   "channel %d NAPI poll executing on CPU %d\n",
 		   channel->channel, raw_smp_processor_id());
@@ -335,7 +332,6 @@ static int efx_poll(struct napi_struct *napi, int budget)
 		efx_nic_eventq_read_ack(channel);
 	}
 
-	efx_channel_unlock_napi(channel);
 	return spent;
 }
 
@@ -391,7 +387,6 @@ void efx_start_eventq(struct efx_channel *channel)
 	channel->enabled = true;
 	smp_wmb();
 
-	efx_channel_enable(channel);
 	napi_enable(&channel->napi_str);
 	efx_nic_eventq_read_ack(channel);
 }
@@ -403,8 +398,6 @@ void efx_stop_eventq(struct efx_channel *channel)
 		return;
 
 	napi_disable(&channel->napi_str);
-	while (!efx_channel_disable(channel))
-		usleep_range(1000, 20000);
 	channel->enabled = false;
 }
 
@@ -2088,7 +2081,6 @@ static void efx_init_napi_channel(struct efx_channel *channel)
 	channel->napi_dev = efx->net_dev;
 	netif_napi_add(channel->napi_dev, &channel->napi_str,
 		       efx_poll, napi_weight);
-	efx_channel_busy_poll_init(channel);
 }
 
 static void efx_init_napi(struct efx_nic *efx)
@@ -2138,37 +2130,6 @@ static void efx_netpoll(struct net_device *net_dev)
 
 #endif
 
-#ifdef CONFIG_NET_RX_BUSY_POLL
-static int efx_busy_poll(struct napi_struct *napi)
-{
-	struct efx_channel *channel =
-		container_of(napi, struct efx_channel, napi_str);
-	struct efx_nic *efx = channel->efx;
-	int budget = 4;
-	int old_rx_packets, rx_packets;
-
-	if (!netif_running(efx->net_dev))
-		return LL_FLUSH_FAILED;
-
-	if (!efx_channel_try_lock_poll(channel))
-		return LL_FLUSH_BUSY;
-
-	old_rx_packets = channel->rx_queue.rx_packets;
-	efx_process_channel(channel, budget);
-
-	rx_packets = channel->rx_queue.rx_packets - old_rx_packets;
-
-	/* There is no race condition with NAPI here.
-	 * NAPI will automatically be rescheduled if it yielded during busy
-	 * polling, because it was not able to take the lock and thus returned
-	 * the full budget.
-	 */
-	efx_channel_unlock_poll(channel);
-
-	return rx_packets;
-}
-#endif
-
 /**************************************************************************
  *
  * Kernel net device interface
@@ -2402,9 +2363,6 @@ static const struct net_device_ops efx_netdev_ops = {
 	.ndo_poll_controller = efx_netpoll,
 #endif
 	.ndo_setup_tc		= efx_setup_tc,
-#ifdef CONFIG_NET_RX_BUSY_POLL
-	.ndo_busy_poll		= efx_busy_poll,
-#endif
 #ifdef CONFIG_RFS_ACCEL
 	.ndo_rx_flow_steer	= efx_filter_rfs,
 #endif