# \[PATCH wireless-next v4 21/21\] wifi: mac80211: define API to invoke SMD Drain Completion event

- From: Pooventhiran G \<hidden\>
- Date: 2026-11-06 08:00:16 
- List: linux-wireless
- Page: https://ratatoskr.run/linux-wireless/2026/11/17876455
- Thread: https://ratatoskr.run/linux-wireless/2026/11/17876429/t.md

```text
To indicate userspace the early termination of the DL draining period,
define an API for drivers to invoke the SMD Drain Completion event. This
API makes sure that the non-AP MLD is already in the DL Drain sub-state
(4c) in the first place to being able to terminate it.

Suggested-by: Rohan Dutta <redacted>
Signed-off-by: Pooventhiran G <redacted>
---
 include/net/mac80211.h | 16 ++++++++++++++++
 net/mac80211/cfg.c     | 18 ++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index d78b7e897230..7dc7d1a7a1f8 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -8331,4 +8331,20 @@ int ieee80211_encrypt_tx_skb(struct sk_buff *skb);
 void ieee80211_get_smd_ctx_done(struct ieee80211_vif *vif,
 				const u8 *sta_addr,
 				struct cfg80211_smd_transition_info *st_info);
+
+/**
+ * ieee80211_notify_smd_drain_completion - notify downlink drain completion for
+ *	an SMD station.
+ * @vif: virtual interface
+ * @station: non-AP MLD object
+ *
+ * The start of DL draining will have moved the station to SMD sub-state
+ * %IEEE80211_STA_SMD_DRAIN. Hence, drain completion is valid only if the
+ * station is already in this state. Should be called under wiphy_lock.
+ *
+ * Return: 0 if success, -EINVAL otherwise
+ */
+int ieee80211_notify_smd_drain_completion(struct ieee80211_vif *vif,
+					  struct ieee80211_sta *station);
+
 #endif /* MAC80211_H */
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 26ebbc27dac0..0aafc7ac771c 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -6423,6 +6423,24 @@ void ieee80211_get_smd_ctx_done(struct ieee80211_vif *vif,
 }
 EXPORT_SYMBOL(ieee80211_get_smd_ctx_done);
 
+int ieee80211_notify_smd_drain_completion(struct ieee80211_vif *vif,
+					  struct ieee80211_sta *station)
+{
+	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
+	struct sta_info *sta = container_of(station, struct sta_info, sta);
+
+	lockdep_assert_wiphy(sdata->local->hw.wiphy);
+
+	/* doesn't make sense to terminate if we are not draining already */
+	if (sta->smd_state != IEEE80211_STA_SMD_DRAIN)
+		return -EINVAL;
+
+	cfg80211_notify_smd_drain_completion(&sdata->wdev, sta->addr);
+
+	return 0;
+}
+EXPORT_SYMBOL(ieee80211_notify_smd_drain_completion);
+
 const struct cfg80211_ops mac80211_config_ops = {
 	.add_virtual_intf = ieee80211_add_iface,
 	.del_virtual_intf = ieee80211_del_iface,

-- 
2.34.1

```