net: Move {l,t,d}stats allocation to core and convert veth & vrf

Move {l,t,d}stats allocation to the core and let netdevs pick the stats
type they need. That way the driver doesn't have to bother with error
handling (allocation failure checking, making sure free happens in the
right spot, etc) - all happening in the core.

Co-developed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Cc: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20231114004220.6495-3-daniel@iogearbox.net
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 9980517ed8b0d1bbe26083a8fcdfd217a58bfd63..ac030c241d1a56217360e51dcaf29d6dd24dc7f9 100644 (file)
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -1506,25 +1506,12 @@ static void veth_free_queues(struct net_device *dev)
 
 static int veth_dev_init(struct net_device *dev)
 {
-       int err;
-
-       dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
-       if (!dev->lstats)
-               return -ENOMEM;
-
-       err = veth_alloc_queues(dev);
-       if (err) {
-               free_percpu(dev->lstats);
-               return err;
-       }
-
-       return 0;
+       return veth_alloc_queues(dev);
 }
 
 static void veth_dev_free(struct net_device *dev)
 {
        veth_free_queues(dev);
-       free_percpu(dev->lstats);
 }
 
 #ifdef CONFIG_NET_POLL_CONTROLLER
@@ -1796,6 +1783,7 @@ static void veth_setup(struct net_device *dev)
                               NETIF_F_HW_VLAN_STAG_RX);
        dev->needs_free_netdev = true;
        dev->priv_destructor = veth_dev_free;
+       dev->pcpu_stat_type = NETDEV_PCPU_STAT_LSTATS;
        dev->max_mtu = ETH_MAX_MTU;
 
        dev->hw_features = VETH_FEATURES;

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 3e6e0fdc3ba7f0b89d1c1a9836da0a3f4cb7bf7d..bb95ce43cd97d3827e3499ca29bb2f8b51961e1d 100644 (file)
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -1164,22 +1164,15 @@ static void vrf_dev_uninit(struct net_device *dev)
 
        vrf_rtable_release(dev, vrf);
        vrf_rt6_release(dev, vrf);
-
-       free_percpu(dev->dstats);
-       dev->dstats = NULL;
 }
 
 static int vrf_dev_init(struct net_device *dev)
 {
        struct net_vrf *vrf = netdev_priv(dev);
 
-       dev->dstats = netdev_alloc_pcpu_stats(struct pcpu_dstats);
-       if (!dev->dstats)
-               goto out_nomem;
-
        /* create the default dst which points back to us */
        if (vrf_rtable_create(dev) != 0)
-               goto out_stats;
+               goto out_nomem;
 
        if (vrf_rt6_create(dev) != 0)
                goto out_rth;
@@ -1193,9 +1186,6 @@ static int vrf_dev_init(struct net_device *dev)
 
 out_rth:
        vrf_rtable_release(dev, vrf);
-out_stats:
-       free_percpu(dev->dstats);
-       dev->dstats = NULL;
 out_nomem:
        return -ENOMEM;
 }
@@ -1694,6 +1684,8 @@ static void vrf_setup(struct net_device *dev)
        dev->min_mtu = IPV6_MIN_MTU;
        dev->max_mtu = IP6_MAX_MTU;
        dev->mtu = dev->max_mtu;
+
+       dev->pcpu_stat_type = NETDEV_PCPU_STAT_DSTATS;
 }
 
 static int vrf_validate(struct nlattr *tb[], struct nlattr *data[],

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 98082113156e5a26f64fd045a7c8338d5692037b..2564e209465ea8c1cac107402e51c8562eff047e 100644 (file)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1797,6 +1797,13 @@ enum netdev_ml_priv_type {
        ML_PRIV_CAN,
 };
 
+enum netdev_stat_type {
+       NETDEV_PCPU_STAT_NONE,
+       NETDEV_PCPU_STAT_LSTATS, /* struct pcpu_lstats */
+       NETDEV_PCPU_STAT_TSTATS, /* struct pcpu_sw_netstats */
+       NETDEV_PCPU_STAT_DSTATS, /* struct pcpu_dstats */
+};
+
 /**
  *     struct net_device - The DEVICE structure.
  *
@@ -1991,10 +1998,14 @@ enum netdev_ml_priv_type {
  *
  *     @ml_priv:       Mid-layer private
  *     @ml_priv_type:  Mid-layer private type
- *     @lstats:        Loopback statistics
- *     @tstats:        Tunnel statistics
- *     @dstats:        Dummy statistics
- *     @vstats:        Virtual ethernet statistics
+ *
+ *     @pcpu_stat_type:        Type of device statistics which the core should
+ *                             allocate/free: none, lstats, tstats, dstats. none
+ *                             means the driver is handling statistics allocation/
+ *                             freeing internally.
+ *     @lstats:                Loopback statistics: packets, bytes
+ *     @tstats:                Tunnel statistics: RX/TX packets, RX/TX bytes
+ *     @dstats:                Dummy statistics: RX/TX/drop packets, RX/TX bytes
  *
  *     @garp_port:     GARP
  *     @mrp_port:      MRP
@@ -2354,6 +2365,7 @@ struct net_device {
        void                            *ml_priv;
        enum netdev_ml_priv_type        ml_priv_type;
 
+       enum netdev_stat_type           pcpu_stat_type:8;
        union {
                struct pcpu_lstats __percpu             *lstats;
                struct pcpu_sw_netstats __percpu        *tstats;

diff --git a/net/core/dev.c b/net/core/dev.c
index af53f6d838ce9e5ec73570d31ac39b9f36b1c5c5..0cc6e283edba9b983c7b92c37ff755b04f1fbb64 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10051,6 +10051,46 @@ void netif_tx_stop_all_queues(struct net_device *dev)
 }
 EXPORT_SYMBOL(netif_tx_stop_all_queues);
 
+static int netdev_do_alloc_pcpu_stats(struct net_device *dev)
+{
+       void __percpu *v;
+
+       switch (dev->pcpu_stat_type) {
+       case NETDEV_PCPU_STAT_NONE:
+               return 0;
+       case NETDEV_PCPU_STAT_LSTATS:
+               v = dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
+               break;
+       case NETDEV_PCPU_STAT_TSTATS:
+               v = dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
+               break;
+       case NETDEV_PCPU_STAT_DSTATS:
+               v = dev->dstats = netdev_alloc_pcpu_stats(struct pcpu_dstats);
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       return v ? 0 : -ENOMEM;
+}
+
+static void netdev_do_free_pcpu_stats(struct net_device *dev)
+{
+       switch (dev->pcpu_stat_type) {
+       case NETDEV_PCPU_STAT_NONE:
+               return;
+       case NETDEV_PCPU_STAT_LSTATS:
+               free_percpu(dev->lstats);
+               break;
+       case NETDEV_PCPU_STAT_TSTATS:
+               free_percpu(dev->tstats);
+               break;
+       case NETDEV_PCPU_STAT_DSTATS:
+               free_percpu(dev->dstats);
+               break;
+       }
+}
+
 /**
  * register_netdevice() - register a network device
  * @dev: device to register
@@ -10111,9 +10151,13 @@ int register_netdevice(struct net_device *dev)
                goto err_uninit;
        }
 
+       ret = netdev_do_alloc_pcpu_stats(dev);
+       if (ret)
+               goto err_uninit;
+
        ret = dev_index_reserve(net, dev->ifindex);
        if (ret < 0)
-               goto err_uninit;
+               goto err_free_pcpu;
        dev->ifindex = ret;
 
        /* Transfer changeable features to wanted_features and enable
@@ -10219,6 +10263,8 @@ err_uninit_notify:
        call_netdevice_notifiers(NETDEV_PRE_UNINIT, dev);
 err_ifindex_release:
        dev_index_release(net, dev->ifindex);
+err_free_pcpu:
+       netdev_do_free_pcpu_stats(dev);
 err_uninit:
        if (dev->netdev_ops->ndo_uninit)
                dev->netdev_ops->ndo_uninit(dev);
@@ -10471,6 +10517,7 @@ void netdev_run_todo(void)
                WARN_ON(rcu_access_pointer(dev->ip_ptr));
                WARN_ON(rcu_access_pointer(dev->ip6_ptr));
 
+               netdev_do_free_pcpu_stats(dev);
                if (dev->priv_destructor)
                        dev->priv_destructor(dev);
                if (dev->needs_free_netdev)