Re: [PATCH 7/8] bus: remove per bus scan mode

Kevin Traynor
2026-03-24T16:02:21Z

On 3/23/26 10:53 AM, David Marchand wrote:
> Following the refactoring of device selection, it becomes more apparent
> that there is no need for a per bus scan mode.
> -a / -b options are mutually exclusive.
> --vdev option works in parallel of allow/block list scan mode.
>

-a/-b are mutually exclusive but does it mean "-a 0000:01:00.0" stops
default probe for all devices on other buses ? Is it a change in behavior ?

(I could probably test but I guess you thought about this case given the
nature of patch.)

> Remove this (internal) notion.
>
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
> lib/eal/common/eal_common_bus.c | 20 ++++++++++++++++++-
> lib/eal/common/eal_common_devargs.c | 8 +++-----
> lib/eal/common/eal_private.h | 31 +++++++++++++++++++++++++++++
> lib/eal/include/bus_driver.h | 18 -----------------
> 4 files changed, 53 insertions(+), 24 deletions(-)
>
> diff --git a/lib/eal/common/eal_common_bus.c b/lib/eal/common/eal_common_bus.c
> index 2ca0af7914..27a31bbefa 100644
> --- a/lib/eal/common/eal_common_bus.c
> +++ b/lib/eal/common/eal_common_bus.c
> @@ -18,6 +18,8 @@
> static struct rte_bus_list rte_bus_list =
> TAILQ_HEAD_INITIALIZER(rte_bus_list);
>
> +static enum rte_bus_scan_mode bus_scan_mode;
> +
> RTE_EXPORT_SYMBOL(rte_bus_name)
> const char *
> rte_bus_name(const struct rte_bus *bus)
> @@ -252,7 +254,7 @@ rte_bus_is_ignored_device(const struct rte_bus *bus, const char *dev_name)
> {
> struct rte_devargs *devargs = rte_bus_find_devargs(bus, dev_name);
>
> - switch (bus->conf.scan_mode) {
> + switch (rte_bus_scan_mode_get()) {
> case RTE_BUS_SCAN_ALLOWLIST:
> if (devargs && devargs->policy == RTE_DEV_ALLOWED)
> return false;
> @@ -266,6 +268,22 @@ rte_bus_is_ignored_device(const struct rte_bus *bus, const char *dev_name)
> return true;
> }
>
> +enum rte_bus_scan_mode
> +rte_bus_scan_mode_get(void)
> +{
> + return bus_scan_mode;
> +}
> +
> +int
> +rte_bus_scan_mode_set(enum rte_bus_scan_mode scan_mode)
> +{
> + if (bus_scan_mode != RTE_BUS_SCAN_UNDEFINED)
> + return -EINVAL;
> +
> + bus_scan_mode = scan_mode;
> + return 0;
> +}
> +
> /*
> * Get iommu class of devices on the bus.
> */
> diff --git a/lib/eal/common/eal_common_devargs.c b/lib/eal/common/eal_common_devargs.c
> index c523429d67..8083bdebc2 100644
> --- a/lib/eal/common/eal_common_devargs.c
> +++ b/lib/eal/common/eal_common_devargs.c
> @@ -330,7 +330,6 @@ int
> rte_devargs_add(enum rte_devtype devtype, const char *devargs_str)
> {
> struct rte_devargs *devargs = NULL;
> - struct rte_bus *bus = NULL;
> const char *dev = devargs_str;
>
> /* use calloc instead of rte_zmalloc as it's called early at init */
> @@ -341,14 +340,13 @@ rte_devargs_add(enum rte_devtype devtype, const char *devargs_str)
> if (rte_devargs_parse(devargs, dev))
> goto fail;
> devargs->type = devtype;
> - bus = devargs->bus;
> if (devargs->type == RTE_DEVTYPE_BLOCKED)
> devargs->policy = RTE_DEV_BLOCKED;
> - if (bus->conf.scan_mode == RTE_BUS_SCAN_UNDEFINED) {
> + if (rte_bus_scan_mode_get() == RTE_BUS_SCAN_UNDEFINED) {
> if (devargs->policy == RTE_DEV_ALLOWED)
> - bus->conf.scan_mode = RTE_BUS_SCAN_ALLOWLIST;
> + rte_bus_scan_mode_set(RTE_BUS_SCAN_ALLOWLIST);
> else if (devargs->policy == RTE_DEV_BLOCKED)
> - bus->conf.scan_mode = RTE_BUS_SCAN_BLOCKLIST;
> + rte_bus_scan_mode_set(RTE_BUS_SCAN_BLOCKLIST);
> }
> TAILQ_INSERT_TAIL(&devargs_list, devargs, next);
> return 0;
> diff --git a/lib/eal/common/eal_private.h b/lib/eal/common/eal_private.h
> index e032dd10c9..12db04dce2 100644
> --- a/lib/eal/common/eal_private.h
> +++ b/lib/eal/common/eal_private.h
> @@ -469,6 +469,37 @@ int rte_eal_memory_detach(void);
> */
> struct rte_bus *rte_bus_find_by_device_name(const char *str);
>
> +/**
> + * Bus scan policies
> + */
> +enum rte_bus_scan_mode {
> + RTE_BUS_SCAN_UNDEFINED,
> + RTE_BUS_SCAN_ALLOWLIST,
> + RTE_BUS_SCAN_BLOCKLIST,
> +};
> +
> +/**
> + * Retrieve the current bus scanning mode.
> + *
> + * @return
> + * The current bus scanning mode.
> + */
> +enum rte_bus_scan_mode rte_bus_scan_mode_get(void);
> +
> +/**
> + * Change the bus scanning mode.
> + * Changing the mode can only be done once from undefined to allow list or to block list.
> + * No change from allow to block (or vice versa) is allowed.
> + *
> + * @param scan_mode
> + * The scanning mode to apply.
> + *
> + * @return
> + * 0 on successful change.
> + * < 0 on failure.
> + */
> +int rte_bus_scan_mode_set(enum rte_bus_scan_mode scan_mode);
> +
> /**
> * For each device on the buses, call the driver-specific function for
> * device cleanup.
> diff --git a/lib/eal/include/bus_driver.h b/lib/eal/include/bus_driver.h
> index e67e052404..9045d64816 100644
> --- a/lib/eal/include/bus_driver.h
> +++ b/lib/eal/include/bus_driver.h
> @@ -232,23 +232,6 @@ typedef int (*rte_bus_sigbus_handler_t)(const void *failure_addr);
> */
> typedef int (*rte_bus_cleanup_t)(void);
>
> -/**
> - * Bus scan policies
> - */
> -enum rte_bus_scan_mode {
> - RTE_BUS_SCAN_UNDEFINED,
> - RTE_BUS_SCAN_ALLOWLIST,
> - RTE_BUS_SCAN_BLOCKLIST,
> -};
> -
> -/**
> - * A structure used to configure bus operations.
> - */
> -struct rte_bus_conf {
> - enum rte_bus_scan_mode scan_mode; /**< Scan policy. */
> -};
> -
> -
> /**
> * Get common iommu class of the all the devices on the bus. The bus may
> * check that those devices are attached to iommu driver.
> @@ -277,7 +260,6 @@ struct rte_bus {
> rte_bus_devargs_parse_t devargs_parse; /**< Parse bus devargs */
> rte_dev_dma_map_t dma_map; /**< DMA map for device in the bus */
> rte_dev_dma_unmap_t dma_unmap; /**< DMA unmap for device in the bus */
> - struct rte_bus_conf conf; /**< Bus configuration */
> rte_bus_get_iommu_class_t get_iommu_class; /**< Get iommu class */
> rte_dev_iterate_t dev_iterate; /**< Device iterator. */
> rte_bus_hot_unplug_handler_t hot_unplug_handler;