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alistair23-linux/net/8021q
Jakub Kicinski c269a24ce0 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>
2021-01-08 19:27:41 -08:00
..
Kconfig treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
Makefile net: remove blank lines at end of file 2018-07-24 14:10:43 -07:00
vlan.c net: make free_netdev() more lenient with unregistering devices 2021-01-08 19:27:41 -08:00
vlan.h net: vlan: Avoid using BUG() in vlan_proto_idx() 2020-09-25 14:12:18 -07:00
vlan_core.c net: vlan: suppress "failed to kill vid" warnings 2020-02-17 14:30:54 -08:00
vlan_dev.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
vlan_gvrp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
vlan_mvrp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
vlan_netlink.c vlan: vlan_changelink() should propagate errors 2020-01-07 13:35:14 -08:00
vlanproc.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
vlanproc.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00