On Sat, Feb 11, 2023 at 10:03:11PM -0500, Alan Stern wrote: > On Sat, Feb 11, 2023 at 09:46:42PM -0500, Kent Overstreet wrote: > > On Sat, Feb 11, 2023 at 09:40:58PM -0500, Alan Stern wrote: > > > Or maybe you're referring to what this patch does? It does indeed > > > create a bunch of dynamic classes -- one for each struct device. The > > > ordering rules derived by lockdep will be somewhat arbitrary, as you > > > say. But some of them certainly will be related to the structure of the > > > source code. > > > > I could be :) I haven't been able to find the patch in question - have a > > link? > > It was earlier in this email thread. Here's a link: > > https://lore.kernel.org/r/Y+gLd78vChQERZ6A@xxxxxxxxxxxxxxxxxxx/ > > > If you're talking about making lock_class_key dynamic, I think I stand > > by what I said though - OTOH, if all you're doing is lifting that to the > > caller of the device object init function, so it'll still be a static > > object in the driver, that would be totally fine. > > The patch does the first, not the second. Feel free to object some > more... :-) So IMO the more correct way to do this would be to change device_initialize() to __device_initialize(), have it take a lock_class_key as a parameter, and then use __mutex_init() instead of mutex_init(). But let's think about this more. Will there ever be situations where lock ordering is dependent on what hardware is plugged into what, or what hardware is plugged in first?
