On Fri, Jan 13, 2023 at 03:12:40PM +0100, Andrew Lunn wrote: > On Thu, Jan 12, 2023 at 09:37:55PM -0800, Jakub Kicinski wrote: > > On Wed, 11 Jan 2023 12:56:07 +0100 Clément Léger wrote: > > > Add support for vlan operation (add, del, filtering) on the RZN1 > > > driver. The a5psw switch supports up to 32 VLAN IDs with filtering, > > > tagged/untagged VLANs and PVID for each ports. > > > > noob question - do you need that mutex? > > aren't those ops all under rtnl_lock? > > Hi Jakub > > Not commenting about this specific patch, but not everything in DSA is > done under RTNL. So you need to deal with some parallel API calls. But > they tend to be in different areas. I would not expect to see two VLAN > changes as the same time, but maybe VLAN and polling in a workqueue to > update the statistics for example could happen. Depending on the > switch, some protect might be needed to stop these operations > interfering with each other. And DSA drivers in general tend to KISS > and over lock. Nothing here is particularly hot path, the switch > itself is on the end of a slow bus, so the overhead of locks are > minimum. That being said, port_vlan_add(), port_vlan_del() and port_vlan_filtering() are all serialized by the rtnl_lock().
