net/vsockmon: Leverage core stats allocator

With commit 34d21de ("net: Move {l,t,d}stats allocation to core and
convert veth & vrf"), stats allocation could be done on net core
instead of this driver.

With this new approach, the driver doesn't have to bother with error
handling (allocation failure checking, making sure free happens in the
right spot, etc). This is core responsibility now.

Remove the allocation in the vsockmon driver and leverage the network
core allocation instead.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20240223115839.3572852-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/vsockmon.c

@@ -13,19 +13,6 @@
 #define DEFAULT_MTU (VIRTIO_VSOCK_MAX_PKT_BUF_SIZE + \
 		     sizeof(struct af_vsockmon_hdr))
 
-static int vsockmon_dev_init(struct net_device *dev)
-{
-	dev->lstats = netdev_alloc_pcpu_stats(struct pcpu_lstats);
-	if (!dev->lstats)
-		return -ENOMEM;
-	return 0;
-}
-
-static void vsockmon_dev_uninit(struct net_device *dev)
-{
-	free_percpu(dev->lstats);
-}
-
 struct vsockmon {
 	struct vsock_tap vt;
 };
@@ -79,8 +66,6 @@ static int vsockmon_change_mtu(struct net_device *dev, int new_mtu)
 }
 
 static const struct net_device_ops vsockmon_ops = {
-	.ndo_init = vsockmon_dev_init,
-	.ndo_uninit = vsockmon_dev_uninit,
 	.ndo_open = vsockmon_open,
 	.ndo_stop = vsockmon_close,
 	.ndo_start_xmit = vsockmon_xmit,
@@ -112,6 +97,7 @@ static void vsockmon_setup(struct net_device *dev)
 	dev->flags = IFF_NOARP;
 
 	dev->mtu = DEFAULT_MTU;
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_LSTATS;
 }
 
 static struct rtnl_link_ops vsockmon_link_ops __read_mostly = {