Re: [RFC v2 4/5] bus: factorize device selection

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, Feb 26, 2026 at 05:20:55PM +0100, David Marchand 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@redhat.com>
> ---
>  drivers/bus/auxiliary/auxiliary_common.c | 15 +----------
>  drivers/bus/cdx/cdx.c                    | 21 +---------------
>  drivers/bus/dpaa/dpaa_bus.c              | 24 ++++++------------
>  drivers/bus/fslmc/fslmc_bus.c            | 22 ++++++----------
>  drivers/bus/pci/pci_common.c             | 15 +----------
>  drivers/bus/platform/platform.c          | 28 ++-------------------
>  drivers/bus/uacce/uacce.c                | 22 +---------------
>  drivers/bus/vmbus/vmbus_common.c         | 21 +---------------
>  drivers/dma/idxd/idxd_bus.c              | 32 +++++++++---------------
>  lib/eal/common/eal_common_bus.c          | 18 +++++++++++++
>  lib/eal/include/bus_driver.h             |  7 ++++++
>  11 files changed, 58 insertions(+), 167 deletions(-)
> 

<snip>

> diff --git a/lib/eal/common/eal_common_bus.c b/lib/eal/common/eal_common_bus.c
> index 0a2311a342..fbe20cfe35 100644
> --- a/lib/eal/common/eal_common_bus.c
> +++ b/lib/eal/common/eal_common_bus.c
> @@ -8,6 +8,7 @@
>  
>  #include <bus_driver.h>
>  #include <rte_debug.h>
> +#include <rte_devargs.h>
>  #include <rte_string_fns.h>
>  #include <rte_errno.h>
>  
> @@ -226,6 +227,23 @@ rte_bus_find_by_device_name(const char *str)
>  	return rte_bus_find(NULL, bus_can_parse, name);
>  }
>  
> +RTE_EXPORT_INTERNAL_SYMBOL(rte_bus_is_ignored_device)
> +bool
> +rte_bus_is_ignored_device(const struct rte_bus *bus, const struct rte_devargs *devargs)
> +{
> +	switch (bus->conf.scan_mode) {
> +	case RTE_BUS_SCAN_ALLOWLIST:
> +		if (devargs && devargs->policy == RTE_DEV_ALLOWED)
> +			return false;
> +		break;
> +	case RTE_BUS_SCAN_UNDEFINED:
> +	case RTE_BUS_SCAN_BLOCKLIST:
> +		if (devargs == NULL || devargs->policy != RTE_DEV_BLOCKED)
> +			return false;
> +		break;
> +	}
> +	return true;
> +}

I think this could do with more comments. Am I right in thinking that
devargs is NULL on input if the device in question is not referenced by any
devargs passed to the app? This seems a little obscure form of input
parameter, so I definitely think it needs documenting.

Is there any way the search for the device name that returns the devargs
null/non-null pointer can be similarly generalized?

>  
>  /*
>   * Get iommu class of devices on the bus.
> diff --git a/lib/eal/include/bus_driver.h b/lib/eal/include/bus_driver.h
> index 60527b75b6..1ec1ff57bb 100644
> --- a/lib/eal/include/bus_driver.h
> +++ b/lib/eal/include/bus_driver.h
> @@ -302,6 +302,13 @@ RTE_INIT_PRIO(businitfn_ ##nm, BUS) \
>  __rte_internal
>  void rte_bus_unregister(struct rte_bus *bus);
>  
> +/**
> + * Indicate if a device referenced by some devargs should be skipped during
> + * probing of a bus.
> + */
> +__rte_internal
> +bool rte_bus_is_ignored_device(const struct rte_bus *bus, const struct rte_devargs *devargs);
> +
>  #ifdef __cplusplus
>  }
>  #endif
> -- 
> 2.53.0
>