Re: [PATCH v5 1/5] wifi: nl80211: add roam offload extended feature

[Arend van Spriel]

On 21/08/2026 09:56, Jason Huang wrote:
> From: Carella Chen <carella.chen@xxxxxxxxxxxx>
>
> Drivers can offload FT or OKC roaming without necessarily
> advertising full 802.1X 4-way handshake offload. Add an extended
> feature bit for that capability and allow PMK configuration when it is
> present.
>
> This gives userspace a way to provide PMK or PMK-R0 material needed
> by firmware roaming implementations while keeping the existing 4-way
> handshake offload capability unchanged.
>
> Assisted-by: GitHub-Copilot-CLI:gpt-5.5
> Signed-off-by: Carella Chen <carella.chen@xxxxxxxxxxxx>
> Signed-off-by: Jason Huang <jason.huang2@xxxxxxxxxxxx>
> ---
>   include/uapi/linux/nl80211.h | 4 ++++
>   net/wireless/nl80211.c       | 7 +++++--
>   2 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
> index 020387d76412..9f8d9e3d5990 100644
> --- a/include/uapi/linux/nl80211.h
> +++ b/include/uapi/linux/nl80211.h
> @@ -7110,6 +7110,9 @@ enum nl80211_feature_flags {
>    * @NL80211_EXT_FEATURE_PROBE_AP: Driver supports probing the associated AP
>    *	in STA mode using @NL80211_CMD_PROBE_PEER.
>    *
> + * @NL80211_EXT_FEATURE_ROAM_OFFLOAD: Driver supports Fast Transition or

Please call it NL80211_EXT_FEATURE_FAST_ROAM_OFFLOAD or simply 
_FAST_ROAMING if the name is getting too long. As long as it is
clear this is not for regular roaming scenario.

> + *	Opportunistic Key Caching roaming offload in station mode.
> + *
>    * @NUM_NL80211_EXT_FEATURES: number of extended features.
>    * @MAX_NL80211_EXT_FEATURES: highest extended feature index.
>    */
> @@ -7192,6 +7195,7 @@ enum nl80211_ext_feature_index {
>   	NL80211_EXT_FEATURE_ROC_ADDR_FILTER,
>   	NL80211_EXT_FEATURE_SET_KEY_LTF_SEED,
>   	NL80211_EXT_FEATURE_PROBE_AP,
> +	NL80211_EXT_FEATURE_ROAM_OFFLOAD,
>   
>   	/* add new features before the definition below */
>   	NUM_NL80211_EXT_FEATURES,
> diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
> index 44f2bad08670..15731440c57a 100644
> --- a/net/wireless/nl80211.c
> +++ b/net/wireless/nl80211.c
> @@ -18434,6 +18434,7 @@ static int nl80211_set_multicast_to_unicast(struct sk_buff *skb,
>   static int nl80211_set_pmk(struct sk_buff *skb, struct genl_info *info)
>   {
>   	struct cfg80211_registered_device *rdev = info->user_ptr[0];
> +	struct wiphy *wiphy = &rdev->wiphy;
>   	struct net_device *dev = info->user_ptr[1];
>   	struct wireless_dev *wdev = dev->ieee80211_ptr;
>   	struct cfg80211_pmk_conf pmk_conf = {};
> @@ -18442,8 +18443,10 @@ static int nl80211_set_pmk(struct sk_buff *skb, struct genl_info *info)
>   	    wdev->iftype != NL80211_IFTYPE_P2P_CLIENT)
>   		return -EOPNOTSUPP;
>   
> -	if (!wiphy_ext_feature_isset(&rdev->wiphy,
> -				     NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_1X))
> +	if (!wiphy_ext_feature_isset(wiphy,
> +				     NL80211_EXT_FEATURE_4WAY_HANDSHAKE_STA_1X) &&
> +	    !wiphy_ext_feature_isset(wiphy,
> +				     NL80211_EXT_FEATURE_ROAM_OFFLOAD))

Ah. _FAST_ROAM_OFFLOAD is not longer than the other ext_feature checked 
here.

>   		return -EOPNOTSUPP;
>   
>   	if (!info->attrs[NL80211_ATTR_MAC] || !info->attrs[NL80211_ATTR_PMK])