Re: [PATCH net-next v17 04/14] net: sfp: Add helper to return the SFP bus name

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Le 09/07/2024 à 08:30, Maxime Chevallier a écrit :
> Knowing the bus name is helpful when we want to expose the link topology
> to userspace, add a helper to return the SFP bus name.
> 
> This call will always be made while holding the RTNL which ensures
> that the SFP driver won't unbind from the device. The returned pointer
> to the bus name will only be used while RTNL is held.
> 
> Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
> Suggested-by: "Russell King (Oracle)" <linux@armlinux.org.uk>

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu>

> ---
>   drivers/net/phy/sfp-bus.c | 22 ++++++++++++++++++++++
>   include/linux/sfp.h       |  6 ++++++
>   2 files changed, 28 insertions(+)
> 
> diff --git a/drivers/net/phy/sfp-bus.c b/drivers/net/phy/sfp-bus.c
> index 56953e66bb7b..f13c00b5b449 100644
> --- a/drivers/net/phy/sfp-bus.c
> +++ b/drivers/net/phy/sfp-bus.c
> @@ -722,6 +722,28 @@ void sfp_bus_del_upstream(struct sfp_bus *bus)
>   }
>   EXPORT_SYMBOL_GPL(sfp_bus_del_upstream);
>   
> +/**
> + * sfp_get_name() - Get the SFP device name
> + * @bus: a pointer to the &struct sfp_bus structure for the sfp module
> + *
> + * Gets the SFP device's name, if @bus has a registered socket. Callers must
> + * hold RTNL, and the returned name is only valid until RTNL is released.
> + *
> + * Returns:
> + *	- The name of the SFP device registered with sfp_register_socket()
> + *	- %NULL if no device was registered on @bus
> + */
> +const char *sfp_get_name(struct sfp_bus *bus)
> +{
> +	ASSERT_RTNL();
> +
> +	if (bus->sfp_dev)
> +		return dev_name(bus->sfp_dev);
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL_GPL(sfp_get_name);
> +
>   /* Socket driver entry points */
>   int sfp_add_phy(struct sfp_bus *bus, struct phy_device *phydev)
>   {
> diff --git a/include/linux/sfp.h b/include/linux/sfp.h
> index 54abb4d22b2e..60c65cea74f6 100644
> --- a/include/linux/sfp.h
> +++ b/include/linux/sfp.h
> @@ -576,6 +576,7 @@ struct sfp_bus *sfp_bus_find_fwnode(const struct fwnode_handle *fwnode);
>   int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
>   			 const struct sfp_upstream_ops *ops);
>   void sfp_bus_del_upstream(struct sfp_bus *bus);
> +const char *sfp_get_name(struct sfp_bus *bus);
>   #else
>   static inline int sfp_parse_port(struct sfp_bus *bus,
>   				 const struct sfp_eeprom_id *id,
> @@ -654,6 +655,11 @@ static inline int sfp_bus_add_upstream(struct sfp_bus *bus, void *upstream,
>   static inline void sfp_bus_del_upstream(struct sfp_bus *bus)
>   {
>   }
> +
> +static inline const char *sfp_get_name(struct sfp_bus *bus)
> +{
> +	return NULL;
> +}
>   #endif
>   
>   #endif