wifi: mac80211: Add support to indicate that a new interface is to be added

Add support to indicate to the driver that an interface is about to be
added so that the driver could prepare its resources early if it needs
so.

Signed-off-by: Ilan Peer <ilan.peer@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20241007144851.e0e8563e1c30.Ifccc96a46a347eb15752caefc9f4eff31f75ed47@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

4 files changed, 57 insertions, 0 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 333e0fae6796..0b8df8ec5a3b 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -4444,6 +4444,12 @@ struct ieee80211_prep_tx_info {
  *	if the requested TID-To-Link mapping can be accepted or not.
  *	If it's not accepted the driver may suggest a preferred mapping and
  *	modify @ttlm parameter with the suggested TID-to-Link mapping.
+ * @prep_add_interface: prepare for interface addition. This can be used by
+ *      drivers to prepare for the addition of a new interface, e.g., allocate
+ *      the needed resources etc. This callback doesn't guarantee that an
+ *      interface with the specified type would be added, and thus drivers that
+ *      implement this callback need to handle such cases. The type is the full
+ *      &enum nl80211_iftype.
  */
 struct ieee80211_ops {
 	void (*tx)(struct ieee80211_hw *hw,
@@ -4828,6 +4834,8 @@ struct ieee80211_ops {
 	enum ieee80211_neg_ttlm_res
 	(*can_neg_ttlm)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 			struct ieee80211_neg_ttlm *ttlm);
+	void (*prep_add_interface)(struct ieee80211_hw *hw,
+				   enum nl80211_iftype type);
 };
 
 /**
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 847304a3a29a..ce9558cd1576 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -194,6 +194,24 @@ static struct wireless_dev *ieee80211_add_iface(struct wiphy *wiphy,
 		}
 	}
 
+	/* Let the driver know that an interface is going to be added.
+	 * Indicate so only for interface types that will be added to the
+	 * driver.
+	 */
+	switch (type) {
+	case NL80211_IFTYPE_AP_VLAN:
+		break;
+	case NL80211_IFTYPE_MONITOR:
+		if (!ieee80211_hw_check(&local->hw, WANT_MONITOR_VIF) ||
+		    !(params->flags & MONITOR_FLAG_ACTIVE))
+			break;
+		fallthrough;
+	default:
+		drv_prep_add_interface(local,
+				       ieee80211_vif_type_p2p(&sdata->vif));
+		break;
+	}
+
 	return wdev;
 }
 
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index d382d9729e85..48bc2da728c0 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -1728,4 +1728,16 @@ drv_can_neg_ttlm(struct ieee80211_local *local,
 
 	return res;
 }
+
+static inline void
+drv_prep_add_interface(struct ieee80211_local *local,
+		       enum nl80211_iftype type)
+{
+	trace_drv_prep_add_interface(local, type);
+	if (local->ops->prep_add_interface)
+		local->ops->prep_add_interface(&local->hw, type);
+
+	trace_drv_return_void(local);
+}
+
 #endif /* __MAC80211_DRIVER_OPS */
diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h
index dc498cd8cd91..e6f0ce8e5d43 100644
--- a/net/mac80211/trace.h
+++ b/net/mac80211/trace.h
@@ -3154,6 +3154,25 @@ TRACE_EVENT(drv_neg_ttlm_res,
 		  LOCAL_PR_ARG, VIF_PR_ARG, __entry->res
 	)
 );
+
+TRACE_EVENT(drv_prep_add_interface,
+	    TP_PROTO(struct ieee80211_local *local,
+		     enum nl80211_iftype type),
+
+	TP_ARGS(local, type),
+	TP_STRUCT__entry(LOCAL_ENTRY
+			 __field(u32, type)
+	),
+
+	TP_fast_assign(LOCAL_ASSIGN;
+		       __entry->type = type;
+	),
+
+	TP_printk(LOCAL_PR_FMT  " type: %u\n ",
+		  LOCAL_PR_ARG, __entry->type
+	)
+);
+
 #endif /* !__MAC80211_DRIVER_TRACE || TRACE_HEADER_MULTI_READ */
 
 #undef TRACE_INCLUDE_PATH