Re: [PATCH net v2 1/4] auxiliary: Support hexadecimal ids

[Leon Romanovsky <leon@kernel.org>]

On Fri, Jul 25, 2025 at 07:02:24AM +0200, Greg Kroah-Hartman wrote:
> On Thu, Jul 24, 2025 at 09:55:59AM -0400, Sean Anderson wrote:
> > On 7/23/25 04:13, Leon Romanovsky wrote:
> > > On Mon, Jul 21, 2025 at 10:29:32AM -0400, Sean Anderson wrote:
> > >> On 7/20/25 04:17, Leon Romanovsky wrote:
> > >> > On Thu, Jul 17, 2025 at 01:12:08PM -0400, Sean Anderson wrote:
> > >> >> On 7/17/25 12:33, Greg Kroah-Hartman wrote:
> > >> > 
> > >> > <...>
> > >> > 
> > >> >> Anyway, if you really think ids should be random or whatever, why not
> > >> >> just ida_alloc one in axiliary_device_init and ignore whatever's
> > >> >> provided? I'd say around half the auxiliary drivers just use 0 (or some
> > >> >> other constant), which is just as deterministic as using the device
> > >> >> address.
> > >> > 
> > >> > I would say that auxiliary bus is not right fit for such devices. This
> > >> > bus was introduced for more complex devices, like the one who has their
> > >> > own ida_alloc logic.
> > >> 
> > >> I'd say that around 2/3 of the auxiliary drivers that have non-constant
> > >> ids use ida_alloc solely for the auxiliary bus and for no other purpose.
> > >> I don't think that's the kind of complexity you're referring to.
> > >> 
> > >> >> Another third use ida_alloc (or xa_alloc) so all that could be
> > >> >> removed.
> > >> > 
> > >> > These ID numbers need to be per-device.
> > >> 
> > >> Why? They are arbitrary with no semantic meaning, right?
> > > 
> > > Yes, officially there is no meaning, and this is how we would like to
> > > keep it.
> > > 
> > > Right now, they are very correlated with with their respective PCI function number.
> > > Is it important? No, however it doesn't mean that we should proactively harm user
> > > experience just because we can do it.
> > > 
> > > [leonro@c ~]$ l /sys/bus/auxiliary/devices/
> > > ,,,
> > > rwxrwxrwx 1 root root 0 Jul 21 15:25 mlx5_core.rdma.0 -> ../../../devices/pci0000:00/0000:00:02.7/0000:0
> > > 8:00.0/mlx5_core.rdma.0
> > > lrwxrwxrwx 1 root root 0 Jul 21 15:25 mlx5_core.rdma.1 -> ../../../devices/pci0000:00/0000:00:02.7/0000:0
> > > 8:00.1/mlx5_core.rdma
> > 
> > Well, I would certainly like to have semantic meaning for ids. But apparently
> > that is only allowed if you can sneak it past the review process.
> 
> Do I need to dust off my "make all ids random" patch again and actually
> merge it just to prevent this from happening?

After weekend thoughts on it. IDs need to be removed from the driver
access. Let's make them global at least.

Thanks

> 
> greg k-h
>