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From: Breno Leitao <leitao@debian.org>
To: kuba@kernel.org,
	davem@davemloft.net,
	pabeni@redhat.com,
	edumazet@google.com,
	Willem de Bruijn <willemdebruijn.kernel@gmail.com>,
	Jason Wang <jasowang@redhat.com>
Cc: netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	horms@kernel.org,
	dsahern@kernel.org
Subject: [PATCH net-next 1/2] net: tuntap: Leverage core stats allocator
Date: Mon,  4 Mar 2024 10:38:07 -0800
Message-ID: <20240304183810.1474883-1-leitao@debian.org>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

With commit 34d21de99cea9 ("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 tun/tap driver and leverage the network
core allocation instead.

Signed-off-by: Breno Leitao <leitao@debian.org>
---
 drivers/net/tun.c | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index be37235af55d..6c594a3c2c37 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -977,20 +977,15 @@ static int tun_net_init(struct net_device *dev)
 	struct ifreq *ifr = tun->ifr;
 	int err;
 
-	dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
-	if (!dev->tstats)
-		return -ENOMEM;
-
 	spin_lock_init(&tun->lock);
 
 	err = security_tun_dev_alloc_security(&tun->security);
-	if (err < 0) {
-		free_percpu(dev->tstats);
+	if (err < 0)
 		return err;
-	}
 
 	tun_flow_init(tun);
 
+	dev->pcpu_stat_type = NETDEV_PCPU_STAT_TSTATS;
 	dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
 			   TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX |
 			   NETIF_F_HW_VLAN_STAG_TX;
@@ -1008,7 +1003,6 @@ static int tun_net_init(struct net_device *dev)
 	if (err < 0) {
 		tun_flow_uninit(tun);
 		security_tun_dev_free_security(tun->security);
-		free_percpu(dev->tstats);
 		return err;
 	}
 	return 0;
@@ -2317,7 +2311,6 @@ static void tun_free_netdev(struct net_device *dev)
 
 	BUG_ON(!(list_empty(&tun->disabled)));
 
-	free_percpu(dev->tstats);
 	tun_flow_uninit(tun);
 	security_tun_dev_free_security(tun->security);
 	__tun_set_ebpf(tun, &tun->steering_prog, NULL);
-- 
2.43.0