On Mon, Mar 22, 2021 at 4:57 PM Rafael J. Wysocki <rafael@xxxxxxxxxx> wrote: > > On Fri, Mar 19, 2021 at 8:21 PM Andy Shevchenko > <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > > > > The decrementation of acpi_device_bus_id->instance_no > > in acpi_device_del() is incorrect, because it may cause > > a duplicate instance number to be allocated next time > > a device with the same acpi_device_bus_id is added. > > > > Replace above mentioned approach by using IDA framework. ... > > + result = ida_simple_get(&acpi_device_bus_id->instance_ida, 0, 255, GFP_KERNEL); > > This is ida_alloc_range(ida, start, (end) - 1, gfp), so I think it > should be 256 above, instead of 255. Ah, good catch! > While at it, though, there can be more than 256 CPU devices easily on > contemporary systems, so I would use a greater number here. Maybe > 4096 and define a symbol for it? I was thinking about it, but there is a problem with the device name, since it will break a lot of code, And taking into account that currently we don't change the behaviour it is good enough per se as a fix. That said, we may extend by an additional patch with a logic like this: res = ida_get(4096) if (res < 0) return res; if (res >= 256) use %04x else use %02x Would it make sense to you? -- With Best Regards, Andy Shevchenko
