[PATCH 6/8] bus: factorize device selection

[Stephen Hemminger]

On Mon, 23 Mar 2026 11:53:00 +0100
David Marchand <david.marchand at redhat.com> wrote:

> All buses (thankfully) implement the same logic when it comes to
> selecting the devices to probe based on -a/-b options.
> As we want to adjust how devices are selected, provide a common helper
> in EAL and use it in the buses.
> 
> Signed-off-by: David Marchand <david.marchand at redhat.com>
> Acked-by: Bruce Richardson <bruce.richardson at intel.com>
> Reviewed-by: Robin Jarry <rjarry at redhat.com>
> ---
> Changes since RFC v2:
> - changed API to query about a device name and hide the devargs meaning
>   in the common code,

AI review found some issues in this one:

**Error**: In `drivers/dma/idxd/idxd_bus.c`, the refactored
`is_for_this_process_use` has a logic error. The old code could set
`retval` to 0 when a device was blocked:

```c
/* Old - retval could be set to 0 */
if (dsa_bus.bus.conf.scan_mode == RTE_BUS_SCAN_ALLOWLIST)
    retval = rte_bus_find_devargs(...) != NULL;
else
    retval = rte_bus_find_devargs(...) == NULL;
```

The new code only ever sets `retval = 1`, never clearing it:

```c
/* New - retval is never set to 0 */
if (retval && !rte_bus_is_ignored_device(&dsa_bus.bus, dev->device.name))
    retval = 1;
```

If a device should be ignored (blocked or not on the allow list),
`rte_bus_is_ignored_device` returns true, the condition is false, and
`retval` stays 1 from the earlier name-matching check. Blocked devices
will incorrectly pass through.

Suggested fix:
```c
if (retval)
    retval = !rte_bus_is_ignored_device(&dsa_bus.bus, dev->device.name);
```