From: netdev-owner@vger.kernel.org [mailto:netdev-owner@vger.kernel.org]
On Behalf Of Xin Long
Sent: Wednesday, May 3, 2017 12:59 AM
On Tue, May 2, 2017 at 7:03 PM, Gao Feng [off-list ref] wrote:

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From: Xin Long [mailto:lucien.xin@gmail.com]
Sent: Tuesday, May 2, 2017 3:56 PM
On Sat, Apr 29, 2017 at 11:51 AM,  [off-list ref] wrote:

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From: Gao Feng <redacted>

[...]

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-static void veth_dev_free(struct net_device *dev)
+static void veth_destructor_free(struct net_device *dev)
 {
        free_percpu(dev->vstats);
+}

not sure why you needed to add this function.
to use free_percpu() directly may be clearer.

Because both of ndo_uninit and destructor need to perform same free

statements.

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It is good at maintain the codes with the common function.

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+
+static void veth_dev_uninit(struct net_device *dev) {

call free_percpu() here, no need to check dev->reg_state.
free_percpu will just return if dev->vstats is NULL.

It would break the original design if don't check the reg_state.
The original logic is that free the resources in the destructor, not in ndo_init.

I got what you're doing now, can you pls try to fix this with:

--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c

@@ -219,10 +219,9 @@ static int veth_dev_init(struct net_device *dev)
        return 0;
 }

-static void veth_dev_free(struct net_device *dev)
+static void veth_dev_uninit(struct net_device *dev)
 {
        free_percpu(dev->vstats);
-       free_netdev(dev);
 }

 #ifdef CONFIG_NET_POLL_CONTROLLER

@@ -279,6 +278,7 @@ static void veth_set_rx_headroom(struct net_device

*dev, int new_hr)

 static const struct net_device_ops veth_netdev_ops = {
        .ndo_init            = veth_dev_init,
+       .ndo_uninit          = veth_dev_uninit,
        .ndo_open            = veth_open,
        .ndo_stop            = veth_close,
        .ndo_start_xmit      = veth_xmit,

@@ -317,7 +317,7 @@ static void veth_setup(struct net_device *dev)
                               NETIF_F_HW_VLAN_STAG_TX |
                               NETIF_F_HW_VLAN_CTAG_RX |
                               NETIF_F_HW_VLAN_STAG_RX);
-       dev->destructor = veth_dev_free;
+       dev->destructor = free_netdev;
        dev->max_mtu = ETH_MAX_MTU;

        dev->hw_features = VETH_FEATURES;

just as what other virtual nic drivers do (vxlan, geneve, macsec, bridge ....)