[PATCH wireless-next] wifi: mac80211: Remove deleted sta links in ieee80211_ml_reconf_work()

[PATCH wireless-next] wifi: mac80211: Remove deleted sta links in ieee80211_ml_reconf_work()

[Lorenzo Bianconi]

Delete stale station links announced in the reconfiguration IE
transmitted by the AP in the beacon frames.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 net/mac80211/mlme.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 5ecd3d1b172df70c6e447351c89f956b6d873c20..00ffc6b355b8d9b4cc078a887199c637c8224992 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -7058,6 +7058,7 @@ static void ieee80211_ml_reconf_work(struct wiphy *wiphy,
 		container_of(work, struct ieee80211_sub_if_data,
 			     u.mgd.ml_reconf_work.work);
 	u16 new_valid_links, new_active_links, new_dormant_links;
+	struct sta_info *sta;
 	int ret;
 
 	if (!sdata->u.mgd.removed_links)
@@ -7093,6 +7094,18 @@ static void ieee80211_ml_reconf_work(struct wiphy *wiphy,
 		}
 	}
 
+	rcu_read_lock();
+	sta = sta_info_get(sdata, sdata->vif.cfg.ap_addr);
+	if (sta) {
+		unsigned long removed_links = sdata->u.mgd.removed_links;
+		unsigned int link_id;
+
+		for_each_set_bit(link_id, &removed_links,
+				 IEEE80211_MLD_MAX_NUM_LINKS)
+			ieee80211_sta_free_link(sta, link_id);
+	}
+	rcu_read_unlock();
+
 	new_dormant_links = sdata->vif.dormant_links & ~sdata->u.mgd.removed_links;
 
 	ret = ieee80211_vif_set_links(sdata, new_valid_links,

---
base-commit: 97492c019da4b62df83255e968b23b81c0315530
change-id: 20260307-mac80211-reconf-remove-sta-link-a47fa95ea7a7

Best regards,
-- 
Lorenzo Bianconi <lorenzo@kernel.org>

Re: [PATCH wireless-next] wifi: mac80211: Remove deleted sta links in ieee80211_ml_reconf_work()

[Lachlan Hodges]

> +	rcu_read_lock();
> +	sta = sta_info_get(sdata, sdata->vif.cfg.ap_addr);
> +	if (sta) {
> +		unsigned long removed_links = sdata->u.mgd.removed_links;
> +		unsigned int link_id;
> +
> +		for_each_set_bit(link_id, &removed_links,
> +				 IEEE80211_MLD_MAX_NUM_LINKS)
> +			ieee80211_sta_free_link(sta, link_id);
> +	}
> +	rcu_read_unlock();
> +

Could use scoped_guard(rcu) instead?

lachlan

Re: [PATCH wireless-next] wifi: mac80211: Remove deleted sta links in ieee80211_ml_reconf_work()

[Lorenzo Bianconi]

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> > +	rcu_read_lock();
> > +	sta = sta_info_get(sdata, sdata->vif.cfg.ap_addr);
> > +	if (sta) {
> > +		unsigned long removed_links = sdata->u.mgd.removed_links;
> > +		unsigned int link_id;
> > +
> > +		for_each_set_bit(link_id, &removed_links,
> > +				 IEEE80211_MLD_MAX_NUM_LINKS)
> > +			ieee80211_sta_free_link(sta, link_id);
> > +	}
> > +	rcu_read_unlock();
> > +
> 
> Could use scoped_guard(rcu) instead?

I do not have a strong opinion here.
@Johannes: Which one do you prefer?

Regards,
Lorenzo

> 
> lachlan

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Re: [PATCH wireless-next] wifi: mac80211: Remove deleted sta links in ieee80211_ml_reconf_work()

[Johannes Berg]

On Sun, 2026-03-08 at 14:28 +0100, Lorenzo Bianconi wrote:
> > > +	rcu_read_lock();
> > > +	sta = sta_info_get(sdata, sdata->vif.cfg.ap_addr);
> > > +	if (sta) {
> > > +		unsigned long removed_links = sdata->u.mgd.removed_links;
> > > +		unsigned int link_id;
> > > +
> > > +		for_each_set_bit(link_id, &removed_links,
> > > +				 IEEE80211_MLD_MAX_NUM_LINKS)
> > > +			ieee80211_sta_free_link(sta, link_id);
> > > +	}
> > > +	rcu_read_unlock();
> > > +
> > 
> > Could use scoped_guard(rcu) instead?
> 
> I do not have a strong opinion here.
> @Johannes: Which one do you prefer?
> 

To answer the literal question: No strong preference I guess, given that
there's no error path here this seems fine, and the scoped version would
just add another indentation level.

But you really should just remove the rcu_read_lock/unlock anyway, it's
not needed since this holds wiphy mutex, which is sufficient to access
the STA table etc.

Also, I think you need ieee80211_sta_remove_link() to tell the driver?

And I realized another thing - this needs to destroy TDLS stations that
were on the link being removed, but maybe that's a separate commit.

johannes

Re: [PATCH wireless-next] wifi: mac80211: Remove deleted sta links in ieee80211_ml_reconf_work()

[Lorenzo Bianconi]

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On Mar 09, Johannes Berg wrote:
> On Sun, 2026-03-08 at 14:28 +0100, Lorenzo Bianconi wrote:
> > > > +	rcu_read_lock();
> > > > +	sta = sta_info_get(sdata, sdata->vif.cfg.ap_addr);
> > > > +	if (sta) {
> > > > +		unsigned long removed_links = sdata->u.mgd.removed_links;
> > > > +		unsigned int link_id;
> > > > +
> > > > +		for_each_set_bit(link_id, &removed_links,
> > > > +				 IEEE80211_MLD_MAX_NUM_LINKS)
> > > > +			ieee80211_sta_free_link(sta, link_id);
> > > > +	}
> > > > +	rcu_read_unlock();
> > > > +
> > > 
> > > Could use scoped_guard(rcu) instead?
> > 
> > I do not have a strong opinion here.
> > @Johannes: Which one do you prefer?
> > 
> 
> To answer the literal question: No strong preference I guess, given that
> there's no error path here this seems fine, and the scoped version would
> just add another indentation level.
> 
> But you really should just remove the rcu_read_lock/unlock anyway, it's
> not needed since this holds wiphy mutex, which is sufficient to access
> the STA table etc.

ack, I will fix it in v2.

> 
> Also, I think you need ieee80211_sta_remove_link() to tell the driver?

I think we already inform the driver running ieee80211_set_active_links() so
ieee80211_sta_remove_link() seems redundant, right?

ieee80211_set_active_links() -> _ieee80211_set_active_links() -> drv_change_sta_links()

> 
> And I realized another thing - this needs to destroy TDLS stations that
> were on the link being removed, but maybe that's a separate commit.

Do you mean ieee80211_teardown_tdls_peers()? Is it done in
_ieee80211_set_active_links() too?

Regards,
Lorenzo

> 
> johannes

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Re: [PATCH wireless-next] wifi: mac80211: Remove deleted sta links in ieee80211_ml_reconf_work()

[Johannes Berg]

On Mon, 2026-03-09 at 09:20 +0100, Lorenzo Bianconi wrote:
> > Also, I think you need ieee80211_sta_remove_link() to tell the driver?
> 
> I think we already inform the driver running ieee80211_set_active_links() so
> ieee80211_sta_remove_link() seems redundant, right?
> 
> ieee80211_set_active_links() -> _ieee80211_set_active_links() -> drv_change_sta_links()

Oh, hmm, yeah, good point!

> > And I realized another thing - this needs to destroy TDLS stations that
> > were on the link being removed, but maybe that's a separate commit.
> 
> Do you mean ieee80211_teardown_tdls_peers()? Is it done in
> _ieee80211_set_active_links() too?

So ... it was all already consistent all along, at least towards the
driver? I totally missed that, sorry. Thanks for checking!

johannes