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authorJakub Kicinski <kuba@kernel.org>2021-01-06 10:40:06 -0800
committerJakub Kicinski <kuba@kernel.org>2021-01-08 19:27:41 -0800
commitc269a24ce057abfc31130960e96ab197ef6ab196 (patch)
treeb79fe7cf795777ab5e5a46d3520929a6607dfea1 /net/8021q
parent2b446e650b418f9a9e75f99852e2f2560cabfa17 (diff)
net: make free_netdev() more lenient with unregistering devices
There are two flavors of handling netdev registration: - ones called without holding rtnl_lock: register_netdev() and unregister_netdev(); and - those called with rtnl_lock held: register_netdevice() and unregister_netdevice(). While the semantics of the former are pretty clear, the same can't be said about the latter. The netdev_todo mechanism is utilized to perform some of the device unregistering tasks and it hooks into rtnl_unlock() so the locked variants can't actually finish the work. In general free_netdev() does not mix well with locked calls. Most drivers operating under rtnl_lock set dev->needs_free_netdev to true and expect core to make the free_netdev() call some time later. The part where this becomes most problematic is error paths. There is no way to unwind the state cleanly after a call to register_netdevice(), since unreg can't be performed fully without dropping locks. Make free_netdev() more lenient, and defer the freeing if device is being unregistered. This allows error paths to simply call free_netdev() both after register_netdevice() failed, and after a call to unregister_netdevice() but before dropping rtnl_lock. Simplify the error paths which are currently doing gymnastics around free_netdev() handling. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/8021q')
-rw-r--r--net/8021q/vlan.c4
1 files changed, 1 insertions, 3 deletions
diff --git a/net/8021q/vlan.c b/net/8021q/vlan.c
index 15bbfaf943fd..8b644113715e 100644
--- a/net/8021q/vlan.c
+++ b/net/8021q/vlan.c
@@ -284,9 +284,7 @@ static int register_vlan_device(struct net_device *real_dev, u16 vlan_id)
return 0;
out_free_newdev:
- if (new_dev->reg_state == NETREG_UNINITIALIZED ||
- new_dev->reg_state == NETREG_UNREGISTERED)
- free_netdev(new_dev);
+ free_netdev(new_dev);
return err;
}