[PATCH net-next] sfc: get rid of custom busy polling code

[PATCH net-next] sfc: get rid of custom busy polling code

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

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>
---
 drivers/net/ethernet/sfc/efx.c        |   42 --------
 drivers/net/ethernet/sfc/net_driver.h |  125 ------------------------
 drivers/net/ethernet/sfc/rx.c         |    3 
 3 files changed, 1 insertion(+), 169 deletions(-)

diff --git a/drivers/net/ethernet/sfc/efx.c b/drivers/net/ethernet/sfc/efx.c
index 466c02805f72a7d1d19a6a342cd8026f20e43a28..fcd4eeecfef4201d4e0b205a14fba2f57a1041ed 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
diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 5927c20ba43fec866aa7249548e3daca9baa084b..73810d2d630ccf4b410002b2d3a72e04c955a7f9 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -491,131 +491,6 @@ struct efx_channel {
 	u32 sync_timestamp_minor;
 };
 
-#ifdef CONFIG_NET_RX_BUSY_POLL
-enum efx_channel_busy_poll_state {
-	EFX_CHANNEL_STATE_IDLE = 0,
-	EFX_CHANNEL_STATE_NAPI = BIT(0),
-	EFX_CHANNEL_STATE_NAPI_REQ_BIT = 1,
-	EFX_CHANNEL_STATE_NAPI_REQ = BIT(1),
-	EFX_CHANNEL_STATE_POLL_BIT = 2,
-	EFX_CHANNEL_STATE_POLL = BIT(2),
-	EFX_CHANNEL_STATE_DISABLE_BIT = 3,
-};
-
-static inline void efx_channel_busy_poll_init(struct efx_channel *channel)
-{
-	WRITE_ONCE(channel->busy_poll_state, EFX_CHANNEL_STATE_IDLE);
-}
-
-/* Called from the device poll routine to get ownership of a channel. */
-static inline bool efx_channel_lock_napi(struct efx_channel *channel)
-{
-	unsigned long prev, old = READ_ONCE(channel->busy_poll_state);
-
-	while (1) {
-		switch (old) {
-		case EFX_CHANNEL_STATE_POLL:
-			/* Ensure efx_channel_try_lock_poll() wont starve us */
-			set_bit(EFX_CHANNEL_STATE_NAPI_REQ_BIT,
-				&channel->busy_poll_state);
-			/* fallthrough */
-		case EFX_CHANNEL_STATE_POLL | EFX_CHANNEL_STATE_NAPI_REQ:
-			return false;
-		default:
-			break;
-		}
-		prev = cmpxchg(&channel->busy_poll_state, old,
-			       EFX_CHANNEL_STATE_NAPI);
-		if (unlikely(prev != old)) {
-			/* This is likely to mean we've just entered polling
-			 * state. Go back round to set the REQ bit.
-			 */
-			old = prev;
-			continue;
-		}
-		return true;
-	}
-}
-
-static inline void efx_channel_unlock_napi(struct efx_channel *channel)
-{
-	/* Make sure write has completed from efx_channel_lock_napi() */
-	smp_wmb();
-	WRITE_ONCE(channel->busy_poll_state, EFX_CHANNEL_STATE_IDLE);
-}
-
-/* Called from efx_busy_poll(). */
-static inline bool efx_channel_try_lock_poll(struct efx_channel *channel)
-{
-	return cmpxchg(&channel->busy_poll_state, EFX_CHANNEL_STATE_IDLE,
-			EFX_CHANNEL_STATE_POLL) == EFX_CHANNEL_STATE_IDLE;
-}
-
-static inline void efx_channel_unlock_poll(struct efx_channel *channel)
-{
-	clear_bit_unlock(EFX_CHANNEL_STATE_POLL_BIT, &channel->busy_poll_state);
-}
-
-static inline bool efx_channel_busy_polling(struct efx_channel *channel)
-{
-	return test_bit(EFX_CHANNEL_STATE_POLL_BIT, &channel->busy_poll_state);
-}
-
-static inline void efx_channel_enable(struct efx_channel *channel)
-{
-	clear_bit_unlock(EFX_CHANNEL_STATE_DISABLE_BIT,
-			 &channel->busy_poll_state);
-}
-
-/* Stop further polling or napi access.
- * Returns false if the channel is currently busy polling.
- */
-static inline bool efx_channel_disable(struct efx_channel *channel)
-{
-	set_bit(EFX_CHANNEL_STATE_DISABLE_BIT, &channel->busy_poll_state);
-	/* Implicit barrier in efx_channel_busy_polling() */
-	return !efx_channel_busy_polling(channel);
-}
-
-#else /* CONFIG_NET_RX_BUSY_POLL */
-
-static inline void efx_channel_busy_poll_init(struct efx_channel *channel)
-{
-}
-
-static inline bool efx_channel_lock_napi(struct efx_channel *channel)
-{
-	return true;
-}
-
-static inline void efx_channel_unlock_napi(struct efx_channel *channel)
-{
-}
-
-static inline bool efx_channel_try_lock_poll(struct efx_channel *channel)
-{
-	return false;
-}
-
-static inline void efx_channel_unlock_poll(struct efx_channel *channel)
-{
-}
-
-static inline bool efx_channel_busy_polling(struct efx_channel *channel)
-{
-	return false;
-}
-
-static inline void efx_channel_enable(struct efx_channel *channel)
-{
-}
-
-static inline bool efx_channel_disable(struct efx_channel *channel)
-{
-	return true;
-}
-#endif /* CONFIG_NET_RX_BUSY_POLL */
-
 /**
  * struct efx_msi_context - Context for each MSI
  * @efx: The associated NIC
diff --git a/drivers/net/ethernet/sfc/rx.c b/drivers/net/ethernet/sfc/rx.c
index 5f4ad4f3518f22ad773e9af4767f065268d7e981..31587f4066ab08f52409b2c666df0b92b4707781 100644
--- a/drivers/net/ethernet/sfc/rx.c
+++ b/drivers/net/ethernet/sfc/rx.c
@@ -665,8 +665,7 @@ void __efx_rx_packet(struct efx_channel *channel)
 	if (unlikely(!(efx->net_dev->features & NETIF_F_RXCSUM)))
 		rx_buf->flags &= ~EFX_RX_PKT_CSUMMED;
 
-	if ((rx_buf->flags & EFX_RX_PKT_TCP) && !channel->type->receive_skb &&
-	    !efx_channel_busy_polling(channel))
+	if ((rx_buf->flags & EFX_RX_PKT_TCP) && !channel->type->receive_skb)
 		efx_rx_packet_gro(channel, rx_buf, channel->rx_pkt_n_frags, eh);
 	else
 		efx_rx_deliver(channel, eh, rx_buf, channel->rx_pkt_n_frags);

[PATCH net-next] sfc-falcon: get rid of custom busy polling code

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

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>
---
 drivers/net/ethernet/sfc/falcon/efx.c        |   42 -----
 drivers/net/ethernet/sfc/falcon/net_driver.h |  125 -----------------
 drivers/net/ethernet/sfc/falcon/rx.c         |    3 
 3 files changed, 1 insertion(+), 169 deletions(-)

diff --git a/drivers/net/ethernet/sfc/falcon/efx.c b/drivers/net/ethernet/sfc/falcon/efx.c
index c4ff3bb1a1ef48724f851b571fd206ae72d2d49f..f5e5cd1659a148fb63ce2078ef13a5ae12d048bc 100644
--- a/drivers/net/ethernet/sfc/falcon/efx.c
+++ b/drivers/net/ethernet/sfc/falcon/efx.c
@@ -304,9 +304,6 @@ static int ef4_poll(struct napi_struct *napi, int budget)
 	struct ef4_nic *efx = channel->efx;
 	int spent;
 
-	if (!ef4_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());
@@ -331,7 +328,6 @@ static int ef4_poll(struct napi_struct *napi, int budget)
 		ef4_nic_eventq_read_ack(channel);
 	}
 
-	ef4_channel_unlock_napi(channel);
 	return spent;
 }
 
@@ -387,7 +383,6 @@ void ef4_start_eventq(struct ef4_channel *channel)
 	channel->enabled = true;
 	smp_wmb();
 
-	ef4_channel_enable(channel);
 	napi_enable(&channel->napi_str);
 	ef4_nic_eventq_read_ack(channel);
 }
@@ -399,8 +394,6 @@ void ef4_stop_eventq(struct ef4_channel *channel)
 		return;
 
 	napi_disable(&channel->napi_str);
-	while (!ef4_channel_disable(channel))
-		usleep_range(1000, 20000);
 	channel->enabled = false;
 }
 
@@ -2029,7 +2022,6 @@ static void ef4_init_napi_channel(struct ef4_channel *channel)
 	channel->napi_dev = efx->net_dev;
 	netif_napi_add(channel->napi_dev, &channel->napi_str,
 		       ef4_poll, napi_weight);
-	ef4_channel_busy_poll_init(channel);
 }
 
 static void ef4_init_napi(struct ef4_nic *efx)
@@ -2079,37 +2071,6 @@ static void ef4_netpoll(struct net_device *net_dev)
 
 #endif
 
-#ifdef CONFIG_NET_RX_BUSY_POLL
-static int ef4_busy_poll(struct napi_struct *napi)
-{
-	struct ef4_channel *channel =
-		container_of(napi, struct ef4_channel, napi_str);
-	struct ef4_nic *efx = channel->efx;
-	int budget = 4;
-	int old_rx_packets, rx_packets;
-
-	if (!netif_running(efx->net_dev))
-		return LL_FLUSH_FAILED;
-
-	if (!ef4_channel_try_lock_poll(channel))
-		return LL_FLUSH_BUSY;
-
-	old_rx_packets = channel->rx_queue.rx_packets;
-	ef4_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.
-	 */
-	ef4_channel_unlock_poll(channel);
-
-	return rx_packets;
-}
-#endif
-
 /**************************************************************************
  *
  * Kernel net device interface
@@ -2289,9 +2250,6 @@ static const struct net_device_ops ef4_netdev_ops = {
 	.ndo_poll_controller = ef4_netpoll,
 #endif
 	.ndo_setup_tc		= ef4_setup_tc,
-#ifdef CONFIG_NET_RX_BUSY_POLL
-	.ndo_busy_poll		= ef4_busy_poll,
-#endif
 #ifdef CONFIG_RFS_ACCEL
 	.ndo_rx_flow_steer	= ef4_filter_rfs,
 #endif
diff --git a/drivers/net/ethernet/sfc/falcon/net_driver.h b/drivers/net/ethernet/sfc/falcon/net_driver.h
index fe59dd67f9186bb9e2282ab00a3e04460ae80bc6..37a8bdf32206a44b82ff25d4111412062dd04a22 100644
--- a/drivers/net/ethernet/sfc/falcon/net_driver.h
+++ b/drivers/net/ethernet/sfc/falcon/net_driver.h
@@ -448,131 +448,6 @@ struct ef4_channel {
 	struct ef4_tx_queue tx_queue[EF4_TXQ_TYPES];
 };
 
-#ifdef CONFIG_NET_RX_BUSY_POLL
-enum ef4_channel_busy_poll_state {
-	EF4_CHANNEL_STATE_IDLE = 0,
-	EF4_CHANNEL_STATE_NAPI = BIT(0),
-	EF4_CHANNEL_STATE_NAPI_REQ_BIT = 1,
-	EF4_CHANNEL_STATE_NAPI_REQ = BIT(1),
-	EF4_CHANNEL_STATE_POLL_BIT = 2,
-	EF4_CHANNEL_STATE_POLL = BIT(2),
-	EF4_CHANNEL_STATE_DISABLE_BIT = 3,
-};
-
-static inline void ef4_channel_busy_poll_init(struct ef4_channel *channel)
-{
-	WRITE_ONCE(channel->busy_poll_state, EF4_CHANNEL_STATE_IDLE);
-}
-
-/* Called from the device poll routine to get ownership of a channel. */
-static inline bool ef4_channel_lock_napi(struct ef4_channel *channel)
-{
-	unsigned long prev, old = READ_ONCE(channel->busy_poll_state);
-
-	while (1) {
-		switch (old) {
-		case EF4_CHANNEL_STATE_POLL:
-			/* Ensure ef4_channel_try_lock_poll() wont starve us */
-			set_bit(EF4_CHANNEL_STATE_NAPI_REQ_BIT,
-				&channel->busy_poll_state);
-			/* fallthrough */
-		case EF4_CHANNEL_STATE_POLL | EF4_CHANNEL_STATE_NAPI_REQ:
-			return false;
-		default:
-			break;
-		}
-		prev = cmpxchg(&channel->busy_poll_state, old,
-			       EF4_CHANNEL_STATE_NAPI);
-		if (unlikely(prev != old)) {
-			/* This is likely to mean we've just entered polling
-			 * state. Go back round to set the REQ bit.
-			 */
-			old = prev;
-			continue;
-		}
-		return true;
-	}
-}
-
-static inline void ef4_channel_unlock_napi(struct ef4_channel *channel)
-{
-	/* Make sure write has completed from ef4_channel_lock_napi() */
-	smp_wmb();
-	WRITE_ONCE(channel->busy_poll_state, EF4_CHANNEL_STATE_IDLE);
-}
-
-/* Called from ef4_busy_poll(). */
-static inline bool ef4_channel_try_lock_poll(struct ef4_channel *channel)
-{
-	return cmpxchg(&channel->busy_poll_state, EF4_CHANNEL_STATE_IDLE,
-			EF4_CHANNEL_STATE_POLL) == EF4_CHANNEL_STATE_IDLE;
-}
-
-static inline void ef4_channel_unlock_poll(struct ef4_channel *channel)
-{
-	clear_bit_unlock(EF4_CHANNEL_STATE_POLL_BIT, &channel->busy_poll_state);
-}
-
-static inline bool ef4_channel_busy_polling(struct ef4_channel *channel)
-{
-	return test_bit(EF4_CHANNEL_STATE_POLL_BIT, &channel->busy_poll_state);
-}
-
-static inline void ef4_channel_enable(struct ef4_channel *channel)
-{
-	clear_bit_unlock(EF4_CHANNEL_STATE_DISABLE_BIT,
-			 &channel->busy_poll_state);
-}
-
-/* Stop further polling or napi access.
- * Returns false if the channel is currently busy polling.
- */
-static inline bool ef4_channel_disable(struct ef4_channel *channel)
-{
-	set_bit(EF4_CHANNEL_STATE_DISABLE_BIT, &channel->busy_poll_state);
-	/* Implicit barrier in ef4_channel_busy_polling() */
-	return !ef4_channel_busy_polling(channel);
-}
-
-#else /* CONFIG_NET_RX_BUSY_POLL */
-
-static inline void ef4_channel_busy_poll_init(struct ef4_channel *channel)
-{
-}
-
-static inline bool ef4_channel_lock_napi(struct ef4_channel *channel)
-{
-	return true;
-}
-
-static inline void ef4_channel_unlock_napi(struct ef4_channel *channel)
-{
-}
-
-static inline bool ef4_channel_try_lock_poll(struct ef4_channel *channel)
-{
-	return false;
-}
-
-static inline void ef4_channel_unlock_poll(struct ef4_channel *channel)
-{
-}
-
-static inline bool ef4_channel_busy_polling(struct ef4_channel *channel)
-{
-	return false;
-}
-
-static inline void ef4_channel_enable(struct ef4_channel *channel)
-{
-}
-
-static inline bool ef4_channel_disable(struct ef4_channel *channel)
-{
-	return true;
-}
-#endif /* CONFIG_NET_RX_BUSY_POLL */
-
 /**
  * struct ef4_msi_context - Context for each MSI
  * @efx: The associated NIC
diff --git a/drivers/net/ethernet/sfc/falcon/rx.c b/drivers/net/ethernet/sfc/falcon/rx.c
index 250458cbdb4dcdd3700bdf520cee8c9865c4abdb..6a8406dc0c2b47dbdb4c2466e028ff04fd35e1c9 100644
--- a/drivers/net/ethernet/sfc/falcon/rx.c
+++ b/drivers/net/ethernet/sfc/falcon/rx.c
@@ -674,8 +674,7 @@ void __ef4_rx_packet(struct ef4_channel *channel)
 	if (unlikely(!(efx->net_dev->features & NETIF_F_RXCSUM)))
 		rx_buf->flags &= ~EF4_RX_PKT_CSUMMED;
 
-	if ((rx_buf->flags & EF4_RX_PKT_TCP) && !channel->type->receive_skb &&
-	    !ef4_channel_busy_polling(channel))
+	if ((rx_buf->flags & EF4_RX_PKT_TCP) && !channel->type->receive_skb)
 		ef4_rx_packet_gro(channel, rx_buf, channel->rx_pkt_n_frags, eh);
 	else
 		ef4_rx_deliver(channel, eh, rx_buf, channel->rx_pkt_n_frags);

Re: [PATCH net-next] sfc-falcon: get rid of custom busy polling code

[Bert Kenward]

On 03/02/17 02:22, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
> 
> 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>

Re: [PATCH net-next] sfc-falcon: get rid of custom busy polling code

[David Miller]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 02 Feb 2017 18:22:28 -0800

> From: Eric Dumazet <edumazet@google.com>
> 
> 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>

Applied.

Re: [PATCH net-next] sfc: get rid of custom busy polling code

[Bert Kenward]

On 03/02/17 01:13, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
> 
> 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>

We were talking about doing this just yesterday.
Thanks Eric.

Acked-by: Bert Kenward <bkenward@solarflare.com>

Re: [PATCH net-next] sfc: get rid of custom busy polling code

[Eric Dumazet]

On Fri, 2017-02-03 at 09:14 +0000, Bert Kenward wrote:
> On 03/02/17 01:13, Eric Dumazet wrote:
> > From: Eric Dumazet <edumazet@google.com>
> > 
> > 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>
> 
> We were talking about doing this just yesterday.
> Thanks Eric.
> 
> Acked-by: Bert Kenward <bkenward@solarflare.com>

Excellent then, thanks !

Re: [PATCH net-next] sfc: get rid of custom busy polling code

[David Miller]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 02 Feb 2017 17:13:19 -0800

> From: Eric Dumazet <edumazet@google.com>
> 
> 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>

Applied.