net: remove dev_txq_stats_fold()

After recent changes, (percpu stats on vlan/tunnels...), we dont need
anymore per struct netdev_queue tx_bytes/tx_packets/tx_dropped counters.

Only remaining users are ixgbe, sch_teql, gianfar & macvlan :

1) ixgbe can be converted to use existing tx_ring counters.

2) macvlan incremented txq->tx_dropped, it can use the
dev->stats.tx_dropped counter.

3) sch_teql : almost revert ab35cd4b8f42 (Use net_device internal stats)
    Now we have ndo_get_stats64(), use it, even for "unsigned long"
fields (No need to bring back a struct net_device_stats)

4) gianfar adds a stats structure per tx queue to hold
tx_bytes/tx_packets

This removes a lockdep warning (and possible lockup) in rndis gadget,
calling dev_get_stats() from hard IRQ context.

Ref: http://www.spinics.net/lists/netdev/msg149202.html

Reported-by: Neil Jones <neiljay@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Jarek Poplawski <jarkao2@gmail.com>
CC: Alexander Duyck <alexander.h.duyck@intel.com>
CC: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
CC: Sandeep Gopalpet <sandeep.kumar@freescale.com>
CC: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
index 45c4b7b..f1d4b45 100644 (file)
--- a/drivers/net/gianfar.c
+++ b/drivers/net/gianfar.c
@@ -433,7 +433,6 @@ static void gfar_init_mac(struct net_device *ndev)
 static struct net_device_stats *gfar_get_stats(struct net_device *dev)
 {
        struct gfar_private *priv = netdev_priv(dev);
-       struct netdev_queue *txq;
        unsigned long rx_packets = 0, rx_bytes = 0, rx_dropped = 0;
        unsigned long tx_packets = 0, tx_bytes = 0;
        int i = 0;
@@ -449,9 +448,8 @@ static struct net_device_stats *gfar_get_stats(struct net_device *dev)
        dev->stats.rx_dropped = rx_dropped;
 
        for (i = 0; i < priv->num_tx_queues; i++) {
-               txq = netdev_get_tx_queue(dev, i);
-               tx_bytes += txq->tx_bytes;
-               tx_packets += txq->tx_packets;
+               tx_bytes += priv->tx_queue[i]->stats.tx_bytes;
+               tx_packets += priv->tx_queue[i]->stats.tx_packets;
        }
 
        dev->stats.tx_bytes = tx_bytes;
@@ -2108,8 +2106,8 @@ static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev)
        }
 
        /* Update transmit stats */
-       txq->tx_bytes += skb->len;
-       txq->tx_packets ++;
+       tx_queue->stats.tx_bytes += skb->len;
+       tx_queue->stats.tx_packets++;
 
        txbdp = txbdp_start = tx_queue->cur_tx;
        lstatus = txbdp->lstatus;

diff --git a/drivers/net/gianfar.h b/drivers/net/gianfar.h
index 68984eb..54de413 100644 (file)
--- a/drivers/net/gianfar.h
+++ b/drivers/net/gianfar.h
@@ -907,12 +907,21 @@ enum {
        MQ_MG_MODE
 };
 
+/*
+ * Per TX queue stats
+ */
+struct tx_q_stats {
+       unsigned long tx_packets;
+       unsigned long tx_bytes;
+};
+
 /**
  *     struct gfar_priv_tx_q - per tx queue structure
  *     @txlock: per queue tx spin lock
  *     @tx_skbuff:skb pointers
  *     @skb_curtx: to be used skb pointer
  *     @skb_dirtytx:the last used skb pointer
+ *     @stats: bytes/packets stats
  *     @qindex: index of this queue
  *     @dev: back pointer to the dev structure
  *     @grp: back pointer to the group to which this queue belongs
@@ -934,6 +943,7 @@ struct gfar_priv_tx_q {
        struct  txbd8 *tx_bd_base;
        struct  txbd8 *cur_tx;
        struct  txbd8 *dirty_tx;
+       struct tx_q_stats stats;
        struct  net_device *dev;
        struct gfar_priv_grp *grp;
        u16     skb_curtx;

diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
index a060610..602078b 100644 (file)
--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c
@@ -6667,8 +6667,6 @@ netdev_tx_t ixgbe_xmit_frame_ring(struct sk_buff *skb,
                          struct ixgbe_adapter *adapter,
                          struct ixgbe_ring *tx_ring)
 {
-       struct net_device *netdev = tx_ring->netdev;
-       struct netdev_queue *txq;
        unsigned int first;
        unsigned int tx_flags = 0;
        u8 hdr_len = 0;
@@ -6765,9 +6763,6 @@ netdev_tx_t ixgbe_xmit_frame_ring(struct sk_buff *skb,
                /* add the ATR filter if ATR is on */
                if (test_bit(__IXGBE_TX_FDIR_INIT_DONE, &tx_ring->state))
                        ixgbe_atr(tx_ring, skb, tx_flags, protocol);
-               txq = netdev_get_tx_queue(netdev, tx_ring->queue_index);
-               txq->tx_bytes += skb->len;
-               txq->tx_packets++;
                ixgbe_tx_queue(tx_ring, tx_flags, count, skb->len, hdr_len);
                ixgbe_maybe_stop_tx(tx_ring, DESC_NEEDED);
 
@@ -6925,8 +6920,6 @@ static struct rtnl_link_stats64 *ixgbe_get_stats64(struct net_device *netdev,
        struct ixgbe_adapter *adapter = netdev_priv(netdev);
        int i;
 
-       /* accurate rx/tx bytes/packets stats */
-       dev_txq_stats_fold(netdev, stats);
        rcu_read_lock();
        for (i = 0; i < adapter->num_rx_queues; i++) {
                struct ixgbe_ring *ring = ACCESS_ONCE(adapter->rx_ring[i]);
@@ -6943,6 +6936,22 @@ static struct rtnl_link_stats64 *ixgbe_get_stats64(struct net_device *netdev,
                        stats->rx_bytes   += bytes;
                }
        }
+
+       for (i = 0; i < adapter->num_tx_queues; i++) {
+               struct ixgbe_ring *ring = ACCESS_ONCE(adapter->tx_ring[i]);
+               u64 bytes, packets;
+               unsigned int start;
+
+               if (ring) {
+                       do {
+                               start = u64_stats_fetch_begin_bh(&ring->syncp);
+                               packets = ring->stats.packets;
+                               bytes   = ring->stats.bytes;
+                       } while (u64_stats_fetch_retry_bh(&ring->syncp, start));
+                       stats->tx_packets += packets;
+                       stats->tx_bytes   += bytes;
+               }
+       }
        rcu_read_unlock();
        /* following stats updated by ixgbe_watchdog_task() */
        stats->multicast        = netdev->stats.multicast;

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 21845af..5933621 100644 (file)
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -585,7 +585,7 @@ err:
        rcu_read_lock_bh();
        vlan = rcu_dereference(q->vlan);
        if (vlan)
-               netdev_get_tx_queue(vlan->dev, 0)->tx_dropped++;
+               vlan->dev->stats.tx_dropped++;
        rcu_read_unlock_bh();
 
        return err;

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index be4957c..d971346 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -520,9 +520,6 @@ struct netdev_queue {
         * please use this field instead of dev->trans_start
         */
        unsigned long           trans_start;
-       u64                     tx_bytes;
-       u64                     tx_packets;
-       u64                     tx_dropped;
 } ____cacheline_aligned_in_smp;
 
 static inline int netdev_queue_numa_node_read(const struct netdev_queue *q)
@@ -2265,8 +2262,6 @@ extern void               dev_load(struct net *net, const char *name);
 extern void            dev_mcast_init(void);
 extern struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
                                               struct rtnl_link_stats64 *storage);
-extern void            dev_txq_stats_fold(const struct net_device *dev,
-                                          struct rtnl_link_stats64 *stats);
 
 extern int             netdev_max_backlog;
 extern int             netdev_tstamp_prequeue;

diff --git a/net/core/dev.c b/net/core/dev.c
index a3ef808..83507c2 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5523,34 +5523,6 @@ void netdev_run_todo(void)
        }
 }
 
-/**
- *     dev_txq_stats_fold - fold tx_queues stats
- *     @dev: device to get statistics from
- *     @stats: struct rtnl_link_stats64 to hold results
- */
-void dev_txq_stats_fold(const struct net_device *dev,
-                       struct rtnl_link_stats64 *stats)
-{
-       u64 tx_bytes = 0, tx_packets = 0, tx_dropped = 0;
-       unsigned int i;
-       struct netdev_queue *txq;
-
-       for (i = 0; i < dev->num_tx_queues; i++) {
-               txq = netdev_get_tx_queue(dev, i);
-               spin_lock_bh(&txq->_xmit_lock);
-               tx_bytes   += txq->tx_bytes;
-               tx_packets += txq->tx_packets;
-               tx_dropped += txq->tx_dropped;
-               spin_unlock_bh(&txq->_xmit_lock);
-       }
-       if (tx_bytes || tx_packets || tx_dropped) {
-               stats->tx_bytes   = tx_bytes;
-               stats->tx_packets = tx_packets;
-               stats->tx_dropped = tx_dropped;
-       }
-}
-EXPORT_SYMBOL(dev_txq_stats_fold);
-
 /* Convert net_device_stats to rtnl_link_stats64.  They have the same
  * fields in the same order, with only the type differing.
  */
@@ -5594,7 +5566,6 @@ struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
                netdev_stats_to_stats64(storage, ops->ndo_get_stats(dev));
        } else {
                netdev_stats_to_stats64(storage, &dev->stats);
-               dev_txq_stats_fold(dev, storage);
        }
        storage->rx_dropped += atomic_long_read(&dev->rx_dropped);
        return storage;

diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index af9360d..84ce48e 100644 (file)
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -59,6 +59,10 @@ struct teql_master
        struct net_device *dev;
        struct Qdisc *slaves;
        struct list_head master_list;
+       unsigned long   tx_bytes;
+       unsigned long   tx_packets;
+       unsigned long   tx_errors;
+       unsigned long   tx_dropped;
 };
 
 struct teql_sched_data
@@ -274,7 +278,6 @@ static inline int teql_resolve(struct sk_buff *skb,
 static netdev_tx_t teql_master_xmit(struct sk_buff *skb, struct net_device *dev)
 {
        struct teql_master *master = netdev_priv(dev);
-       struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
        struct Qdisc *start, *q;
        int busy;
        int nores;
@@ -314,8 +317,8 @@ restart:
                                        __netif_tx_unlock(slave_txq);
                                        master->slaves = NEXT_SLAVE(q);
                                        netif_wake_queue(dev);
-                                       txq->tx_packets++;
-                                       txq->tx_bytes += length;
+                                       master->tx_packets++;
+                                       master->tx_bytes += length;
                                        return NETDEV_TX_OK;
                                }
                                __netif_tx_unlock(slave_txq);
@@ -342,10 +345,10 @@ restart:
                netif_stop_queue(dev);
                return NETDEV_TX_BUSY;
        }
-       dev->stats.tx_errors++;
+       master->tx_errors++;
 
 drop:
-       txq->tx_dropped++;
+       master->tx_dropped++;
        dev_kfree_skb(skb);
        return NETDEV_TX_OK;
 }
@@ -398,6 +401,18 @@ static int teql_master_close(struct net_device *dev)
        return 0;
 }
 
+static struct rtnl_link_stats64 *teql_master_stats64(struct net_device *dev,
+                                                    struct rtnl_link_stats64 *stats)
+{
+       struct teql_master *m = netdev_priv(dev);
+
+       stats->tx_packets       = m->tx_packets;
+       stats->tx_bytes         = m->tx_bytes;
+       stats->tx_errors        = m->tx_errors;
+       stats->tx_dropped       = m->tx_dropped;
+       return stats;
+}
+
 static int teql_master_mtu(struct net_device *dev, int new_mtu)
 {
        struct teql_master *m = netdev_priv(dev);
@@ -422,6 +437,7 @@ static const struct net_device_ops teql_netdev_ops = {
        .ndo_open       = teql_master_open,
        .ndo_stop       = teql_master_close,
        .ndo_start_xmit = teql_master_xmit,
+       .ndo_get_stats64 = teql_master_stats64,
        .ndo_change_mtu = teql_master_mtu,
 };