ixgbevf: 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 code, we also remove one lock
operation in fast path, and allow GRO to do its job.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/ixgbevf/ethtool.c

@@ -432,11 +432,6 @@ static void ixgbevf_get_ethtool_stats(struct net_device *netdev,
 		if (!ring) {
 			data[i++] = 0;
 			data[i++] = 0;
-#ifdef BP_EXTENDED_STATS
-			data[i++] = 0;
-			data[i++] = 0;
-			data[i++] = 0;
-#endif
 			continue;
 		}
 
@@ -446,12 +441,6 @@ static void ixgbevf_get_ethtool_stats(struct net_device *netdev,
 			data[i + 1] = ring->stats.bytes;
 		} while (u64_stats_fetch_retry_irq(&ring->syncp, start));
 		i += 2;
-#ifdef BP_EXTENDED_STATS
-		data[i] = ring->stats.yields;
-		data[i + 1] = ring->stats.misses;
-		data[i + 2] = ring->stats.cleaned;
-		i += 3;
-#endif
 	}
 
 	/* populate Rx queue data */
@@ -460,11 +449,6 @@ static void ixgbevf_get_ethtool_stats(struct net_device *netdev,
 		if (!ring) {
 			data[i++] = 0;
 			data[i++] = 0;
-#ifdef BP_EXTENDED_STATS
-			data[i++] = 0;
-			data[i++] = 0;
-			data[i++] = 0;
-#endif
 			continue;
 		}
 
@@ -474,12 +458,6 @@ static void ixgbevf_get_ethtool_stats(struct net_device *netdev,
 			data[i + 1] = ring->stats.bytes;
 		} while (u64_stats_fetch_retry_irq(&ring->syncp, start));
 		i += 2;
-#ifdef BP_EXTENDED_STATS
-		data[i] = ring->stats.yields;
-		data[i + 1] = ring->stats.misses;
-		data[i + 2] = ring->stats.cleaned;
-		i += 3;
-#endif
 	}
 }
 
@@ -507,28 +485,12 @@ static void ixgbevf_get_strings(struct net_device *netdev, u32 stringset,
 			p += ETH_GSTRING_LEN;
 			sprintf(p, "tx_queue_%u_bytes", i);
 			p += ETH_GSTRING_LEN;
-#ifdef BP_EXTENDED_STATS
-			sprintf(p, "tx_queue_%u_bp_napi_yield", i);
-			p += ETH_GSTRING_LEN;
-			sprintf(p, "tx_queue_%u_bp_misses", i);
-			p += ETH_GSTRING_LEN;
-			sprintf(p, "tx_queue_%u_bp_cleaned", i);
-			p += ETH_GSTRING_LEN;
-#endif /* BP_EXTENDED_STATS */
 		}
 		for (i = 0; i < adapter->num_rx_queues; i++) {
 			sprintf(p, "rx_queue_%u_packets", i);
 			p += ETH_GSTRING_LEN;
 			sprintf(p, "rx_queue_%u_bytes", i);
 			p += ETH_GSTRING_LEN;
-#ifdef BP_EXTENDED_STATS
-			sprintf(p, "rx_queue_%u_bp_poll_yield", i);
-			p += ETH_GSTRING_LEN;
-			sprintf(p, "rx_queue_%u_bp_misses", i);
-			p += ETH_GSTRING_LEN;
-			sprintf(p, "rx_queue_%u_bp_cleaned", i);
-			p += ETH_GSTRING_LEN;
-#endif /* BP_EXTENDED_STATS */
 		}
 		break;
 	}

drivers/net/ethernet/intel/ixgbevf/ixgbevf.h

@@ -37,11 +37,6 @@
 
 #include "vf.h"
 
-#ifdef CONFIG_NET_RX_BUSY_POLL
-#include <net/busy_poll.h>
-#define BP_EXTENDED_STATS
-#endif
-
 #define IXGBE_MAX_TXD_PWR	14
 #define IXGBE_MAX_DATA_PER_TXD	BIT(IXGBE_MAX_TXD_PWR)
 
@@ -73,11 +68,6 @@ struct ixgbevf_rx_buffer {
 struct ixgbevf_stats {
 	u64 packets;
 	u64 bytes;
-#ifdef BP_EXTENDED_STATS
-	u64 yields;
-	u64 misses;
-	u64 cleaned;
-#endif
 };
 
 struct ixgbevf_tx_queue_stats {
@@ -217,109 +207,6 @@ struct ixgbevf_q_vector {
 #endif /* CONFIG_NET_RX_BUSY_POLL */
 };
 
-#ifdef CONFIG_NET_RX_BUSY_POLL
-static inline void ixgbevf_qv_init_lock(struct ixgbevf_q_vector *q_vector)
-{
-	spin_lock_init(&q_vector->lock);
-	q_vector->state = IXGBEVF_QV_STATE_IDLE;
-}
-
-/* called from the device poll routine to get ownership of a q_vector */
-static inline bool ixgbevf_qv_lock_napi(struct ixgbevf_q_vector *q_vector)
-{
-	int rc = true;
-
-	spin_lock_bh(&q_vector->lock);
-	if (q_vector->state & IXGBEVF_QV_LOCKED) {
-		WARN_ON(q_vector->state & IXGBEVF_QV_STATE_NAPI);
-		q_vector->state |= IXGBEVF_QV_STATE_NAPI_YIELD;
-		rc = false;
-#ifdef BP_EXTENDED_STATS
-		q_vector->tx.ring->stats.yields++;
-#endif
-	} else {
-		/* we don't care if someone yielded */
-		q_vector->state = IXGBEVF_QV_STATE_NAPI;
-	}
-	spin_unlock_bh(&q_vector->lock);
-	return rc;
-}
-
-/* returns true is someone tried to get the qv while napi had it */
-static inline bool ixgbevf_qv_unlock_napi(struct ixgbevf_q_vector *q_vector)
-{
-	int rc = false;
-
-	spin_lock_bh(&q_vector->lock);
-	WARN_ON(q_vector->state & (IXGBEVF_QV_STATE_POLL |
-				   IXGBEVF_QV_STATE_NAPI_YIELD));
-
-	if (q_vector->state & IXGBEVF_QV_STATE_POLL_YIELD)
-		rc = true;
-	/* reset state to idle, unless QV is disabled */
-	q_vector->state &= IXGBEVF_QV_STATE_DISABLED;
-	spin_unlock_bh(&q_vector->lock);
-	return rc;
-}
-
-/* called from ixgbevf_low_latency_poll() */
-static inline bool ixgbevf_qv_lock_poll(struct ixgbevf_q_vector *q_vector)
-{
-	int rc = true;
-
-	spin_lock_bh(&q_vector->lock);
-	if ((q_vector->state & IXGBEVF_QV_LOCKED)) {
-		q_vector->state |= IXGBEVF_QV_STATE_POLL_YIELD;
-		rc = false;
-#ifdef BP_EXTENDED_STATS
-		q_vector->rx.ring->stats.yields++;
-#endif
-	} else {
-		/* preserve yield marks */
-		q_vector->state |= IXGBEVF_QV_STATE_POLL;
-	}
-	spin_unlock_bh(&q_vector->lock);
-	return rc;
-}
-
-/* returns true if someone tried to get the qv while it was locked */
-static inline bool ixgbevf_qv_unlock_poll(struct ixgbevf_q_vector *q_vector)
-{
-	int rc = false;
-
-	spin_lock_bh(&q_vector->lock);
-	WARN_ON(q_vector->state & (IXGBEVF_QV_STATE_NAPI));
-
-	if (q_vector->state & IXGBEVF_QV_STATE_POLL_YIELD)
-		rc = true;
-	/* reset state to idle, unless QV is disabled */
-	q_vector->state &= IXGBEVF_QV_STATE_DISABLED;
-	spin_unlock_bh(&q_vector->lock);
-	return rc;
-}
-
-/* true if a socket is polling, even if it did not get the lock */
-static inline bool ixgbevf_qv_busy_polling(struct ixgbevf_q_vector *q_vector)
-{
-	WARN_ON(!(q_vector->state & IXGBEVF_QV_OWNED));
-	return q_vector->state & IXGBEVF_QV_USER_PEND;
-}
-
-/* false if QV is currently owned */
-static inline bool ixgbevf_qv_disable(struct ixgbevf_q_vector *q_vector)
-{
-	int rc = true;
-
-	spin_lock_bh(&q_vector->lock);
-	if (q_vector->state & IXGBEVF_QV_OWNED)
-		rc = false;
-	q_vector->state |= IXGBEVF_QV_STATE_DISABLED;
-	spin_unlock_bh(&q_vector->lock);
-	return rc;
-}
-
-#endif /* CONFIG_NET_RX_BUSY_POLL */
-
 /* microsecond values for various ITR rates shifted by 2 to fit itr register
  * with the first 3 bits reserved 0
  */

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

@@ -457,16 +457,6 @@ static bool ixgbevf_clean_tx_irq(struct ixgbevf_q_vector *q_vector,
 static void ixgbevf_rx_skb(struct ixgbevf_q_vector *q_vector,
 			   struct sk_buff *skb)
 {
-#ifdef CONFIG_NET_RX_BUSY_POLL
-	skb_mark_napi_id(skb, &q_vector->napi);
-
-	if (ixgbevf_qv_busy_polling(q_vector)) {
-		netif_receive_skb(skb);
-		/* exit early if we busy polled */
-		return;
-	}
-#endif /* CONFIG_NET_RX_BUSY_POLL */
-
 	napi_gro_receive(&q_vector->napi, skb);
 }
 
@@ -1031,10 +1021,6 @@ static int ixgbevf_poll(struct napi_struct *napi, int budget)
 
 	if (budget <= 0)
 		return budget;
-#ifdef CONFIG_NET_RX_BUSY_POLL
-	if (!ixgbevf_qv_lock_napi(q_vector))
-		return budget;
-#endif
 
 	/* attempt to distribute budget to each queue fairly, but don't allow
 	 * the budget to go below 1 because we'll exit polling
@@ -1052,10 +1038,6 @@ static int ixgbevf_poll(struct napi_struct *napi, int budget)
 			clean_complete = false;
 	}
 
-#ifdef CONFIG_NET_RX_BUSY_POLL
-	ixgbevf_qv_unlock_napi(q_vector);
-#endif
-
 	/* If all work not completed, return budget and keep polling */
 	if (!clean_complete)
 		return budget;
@@ -1090,40 +1072,6 @@ void ixgbevf_write_eitr(struct ixgbevf_q_vector *q_vector)
 	IXGBE_WRITE_REG(hw, IXGBE_VTEITR(v_idx), itr_reg);
 }
 
-#ifdef CONFIG_NET_RX_BUSY_POLL
-/* must be called with local_bh_disable()d */
-static int ixgbevf_busy_poll_recv(struct napi_struct *napi)
-{
-	struct ixgbevf_q_vector *q_vector =
-			container_of(napi, struct ixgbevf_q_vector, napi);
-	struct ixgbevf_adapter *adapter = q_vector->adapter;
-	struct ixgbevf_ring  *ring;
-	int found = 0;
-
-	if (test_bit(__IXGBEVF_DOWN, &adapter->state))
-		return LL_FLUSH_FAILED;
-
-	if (!ixgbevf_qv_lock_poll(q_vector))
-		return LL_FLUSH_BUSY;
-
-	ixgbevf_for_each_ring(ring, q_vector->rx) {
-		found = ixgbevf_clean_rx_irq(q_vector, ring, 4);
-#ifdef BP_EXTENDED_STATS
-		if (found)
-			ring->stats.cleaned += found;
-		else
-			ring->stats.misses++;
-#endif
-		if (found)
-			break;
-	}
-
-	ixgbevf_qv_unlock_poll(q_vector);
-
-	return found;
-}
-#endif /* CONFIG_NET_RX_BUSY_POLL */
-
 /**
  * ixgbevf_configure_msix - Configure MSI-X hardware
  * @adapter: board private structure
@@ -1960,9 +1908,6 @@ static void ixgbevf_napi_enable_all(struct ixgbevf_adapter *adapter)
 
 	for (q_idx = 0; q_idx < q_vectors; q_idx++) {
 		q_vector = adapter->q_vector[q_idx];
-#ifdef CONFIG_NET_RX_BUSY_POLL
-		ixgbevf_qv_init_lock(adapter->q_vector[q_idx]);
-#endif
 		napi_enable(&q_vector->napi);
 	}
 }
@@ -1976,12 +1921,6 @@ static void ixgbevf_napi_disable_all(struct ixgbevf_adapter *adapter)
 	for (q_idx = 0; q_idx < q_vectors; q_idx++) {
 		q_vector = adapter->q_vector[q_idx];
 		napi_disable(&q_vector->napi);
-#ifdef CONFIG_NET_RX_BUSY_POLL
-		while (!ixgbevf_qv_disable(adapter->q_vector[q_idx])) {
-			pr_info("QV %d locked\n", q_idx);
-			usleep_range(1000, 20000);
-		}
-#endif /* CONFIG_NET_RX_BUSY_POLL */
 	}
 }
 
@@ -3978,9 +3917,6 @@ static const struct net_device_ops ixgbevf_netdev_ops = {
 	.ndo_tx_timeout		= ixgbevf_tx_timeout,
 	.ndo_vlan_rx_add_vid	= ixgbevf_vlan_rx_add_vid,
 	.ndo_vlan_rx_kill_vid	= ixgbevf_vlan_rx_kill_vid,
-#ifdef CONFIG_NET_RX_BUSY_POLL
-	.ndo_busy_poll		= ixgbevf_busy_poll_recv,
-#endif
 #ifdef CONFIG_NET_POLL_CONTROLLER
 	.ndo_poll_controller	= ixgbevf_netpoll,
 #endif