net: geneve: 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 in 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 geneve driver and leverage the network
core allocation instead.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240305172911.502058-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/geneve.c

@@ -319,19 +319,12 @@ static int geneve_init(struct net_device *dev)
 	struct geneve_dev *geneve = netdev_priv(dev);
 	int err;
 
-	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
-	if (!dev->tstats)
-		return -ENOMEM;
-
 	err = gro_cells_init(&geneve->gro_cells, dev);
-	if (err) {
-		free_percpu(dev->tstats);
+	if (err)
 		return err;
-	}
 
 	err = dst_cache_init(&geneve->cfg.info.dst_cache, GFP_KERNEL);
 	if (err) {
-		free_percpu(dev->tstats);
 		gro_cells_destroy(&geneve->gro_cells);
 		return err;
 	}
@@ -345,7 +338,6 @@ static void geneve_uninit(struct net_device *dev)
 
 	dst_cache_destroy(&geneve->cfg.info.dst_cache);
 	gro_cells_destroy(&geneve->gro_cells);
-	free_percpu(dev->tstats);
 }
 
 /* Callback from net/ipv4/udp.c to receive packets */
@@ -1189,6 +1181,7 @@ static void geneve_setup(struct net_device *dev)
 	dev->hw_features |= NETIF_F_RXCSUM;
 	dev->hw_features |= NETIF_F_GSO_SOFTWARE;
 
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
 	/* MTU range: 68 - (something less than 65535) */
 	dev->min_mtu = ETH_MIN_MTU;
 	/* The max_mtu calculation does not take account of GENEVE