On Wed, Feb 24, 2016 at 10:27 PM, Saeed Mahameed <sae...@dev.mellanox.co.il> wrote: >>> Netdev features can be changed dynamically to off after vlan_vid_add >>> was called, thus vlan_vid_del will skip ndo_vlan_rx_kill_vid and will >>> leave the device driver with un-freed resources. >> >> Are you sure the fix isn't to make vlan_vid_add() check ->features instead >> of ->hw_features. > > This is exactly what this fix suggests, "->features" is not consistent > and can be turned ON/OFF between vlan_add/del which can leave the NIC > driver in inconsistent state ! > >> >> Should we really be trying to add VLAN filters when the user has >> turned it off? > > Well, I think it is debatable, but the current implementation is not > consistent, especially for adding vlan 0 by default and then the user > disables the vlan filter, this will cause the stack to never call the > nic ndo_vlan_rx_kill_vid for the pre added vlan 0 and vise versa call > kill_vid without add_vid, BUG ? > > So i think we have two options, use this patch, and always trust to > delegate vlan_vid_add/del to the NIC when it's HW supports it, and the > nic will be smart enough to know what to do with it (in case vlan > filter is enabled/disabled). Or, for each vlan we can remember if it > was added to the NIC or not so the stack will know whether to clean it > up or not.
BTW we choose the first option since the "buggy" function is called "vlan_hw_filter_capable" which lead us to decide that the function should be looking for ->hw_features and not ->features. and i think this way it makes more sense.
