Re: [PATCH net-next v5 1/5] net: dsa: wire flash_update devlink callback to drivers

[Andrew Lunn <andrew@lunn.ch>]

On Sat, Jul 25, 2026 at 03:15:35AM +0100, Daniel Golle wrote:
> Add a devlink_flash_update callback to dsa_switch_ops so that DSA
> drivers can support devlink dev flash without open-coding the devlink
> plumbing. Unlike the other trampolines in net/dsa/devlink.c, the
> flash_update op is only installed for switches whose driver implements
> the callback: the devlink core rejects flash requests up front when the
> op is absent, before fetching the firmware file from userspace, and an
> unconditionally present trampoline would defeat that early check and
> let unsupported requests block on request_firmware() only to fail with
> -EOPNOTSUPP afterwards.

> +/* The devlink core rejects flash requests up front when the flash_update
> + * op is absent, before fetching the firmware file from userspace. Only
> + * install the op for switches whose driver implements it, so that
> + * unsupported requests keep failing early.
> + */
> +#define DSA_DEVLINK_OPS							\
> +	.info_get			= dsa_devlink_info_get,		\
> +	.sb_pool_get			= dsa_devlink_sb_pool_get,	\
> +	.sb_pool_set			= dsa_devlink_sb_pool_set,	\
> +	.sb_port_pool_get		= dsa_devlink_sb_port_pool_get,	\
> +	.sb_port_pool_set		= dsa_devlink_sb_port_pool_set,	\
> +	.sb_tc_pool_bind_get		= dsa_devlink_sb_tc_pool_bind_get, \
> +	.sb_tc_pool_bind_set		= dsa_devlink_sb_tc_pool_bind_set, \
> +	.sb_occ_snapshot		= dsa_devlink_sb_occ_snapshot,	\
> +	.sb_occ_max_clear		= dsa_devlink_sb_occ_max_clear,	\
> +	.sb_occ_port_pool_get		= dsa_devlink_sb_occ_port_pool_get, \
>  	.sb_occ_tc_port_bind_get	= dsa_devlink_sb_occ_tc_port_bind_get,
> +
> +static const struct devlink_ops dsa_devlink_ops = {
> +	DSA_DEVLINK_OPS
> +};

Is this going to scale? How many different permutations are there?

Firmware upgrade is an infrequent operation, so do we actually care
about a request_firmware() which might turn out to be pointless? I
personally would prefer to avoid the scalability issue and just return
-EOPNOTSUPP.

	Andrew