Janusz Dziedzic reported that after a change in wpa_supplicant
["nl80211: Automatically use concurrent P2P if possible"],
carl9170 was no longer able to host a P2P network.
This patch tackles the problem by allowing GO interfaces to be
registered, long after the P2P_CLIENT interface is brought up.
Reported-by: Janusz Dziedzic <janusz.dziedzic@xxxxxxxxx>
Signed-off-by: Christian Lamparter <chunkeey@xxxxxxxxxxxxxx>
---
drivers/net/wireless/ath/carl9170/main.c | 54 ++++++++++++++++++++++++++++--
1 file changed, 51 insertions(+), 3 deletions(-)
diff --git a/drivers/net/wireless/ath/carl9170/main.c b/drivers/net/wireless/ath/carl9170/main.c
index 9dce200..5d3cb88 100644
--- a/drivers/net/wireless/ath/carl9170/main.c
+++ b/drivers/net/wireless/ath/carl9170/main.c
@@ -580,7 +580,7 @@ static int carl9170_op_add_interface(struct ieee80211_hw *hw,
struct ieee80211_vif *vif)
{
struct carl9170_vif_info *vif_priv = (void *) vif->drv_priv;
- struct ieee80211_vif *main_vif;
+ struct ieee80211_vif *main_vif, *old_main = NULL;
struct ar9170 *ar = hw->priv;
int vif_id = -1, err = 0;
@@ -602,6 +602,15 @@ static int carl9170_op_add_interface(struct ieee80211_hw *hw,
goto init;
}
+ /* Because the AR9170 HW's MAC doesn't provide full support for
+ * multiple, independent interfaces [of different operation modes].
+ * We have to select ONE main interface [main mode of HW], but we
+ * can have multiple slaves [AKA: entry in the ACK-table].
+ *
+ * The first (from HEAD/TOP) interface in the ar->vif_list is
+ * always the main intf. All following intfs in this list
+ * are considered to be slave intfs.
+ */
main_vif = carl9170_get_main_vif(ar);
if (main_vif) {
@@ -610,6 +619,18 @@ static int carl9170_op_add_interface(struct ieee80211_hw *hw,
if (vif->type == NL80211_IFTYPE_STATION)
break;
+ /* P2P GO [master] use-case
+ * Because the P2P GO station is selected dynamically
+ * by all participating peers of a WIFI Direct network,
+ * the driver has be able to change the main interface
+ * operating mode on the fly.
+ */
+ if (main_vif->p2p && vif->p2p &&
+ vif->type == NL80211_IFTYPE_AP) {
+ old_main = main_vif;
+ break;
+ }
+
err = -EBUSY;
rcu_read_unlock();
@@ -648,14 +669,41 @@ static int carl9170_op_add_interface(struct ieee80211_hw *hw,
vif_priv->id = vif_id;
vif_priv->enable_beacon = false;
ar->vifs++;
- list_add_tail_rcu(&vif_priv->list, &ar->vif_list);
+ if (old_main) {
+ /* We end up in here, if the main interface is being replaced.
+ * Put the new main interface at the HEAD of the list and the
+ * previous inteface will automatically become second in line.
+ */
+ list_add_rcu(&vif_priv->list, &ar->vif_list);
+ } else {
+ /* Add new inteface. If the list is empty, it will become the
+ * main inteface, otherwise it will be slave.
+ */
+ list_add_tail_rcu(&vif_priv->list, &ar->vif_list);
+ }
rcu_assign_pointer(ar->vif_priv[vif_id].vif, vif);
init:
- if (carl9170_get_main_vif(ar) == vif) {
+ main_vif = carl9170_get_main_vif(ar);
+
+ if (main_vif == vif) {
rcu_assign_pointer(ar->beacon_iter, vif_priv);
rcu_read_unlock();
+ if (old_main) {
+ struct carl9170_vif_info *old_main_priv =
+ (void *) old_main->drv_priv;
+ /* downgrade old main intf to slave intf.
+ * NOTE: We are no longer under rcu_read_lock.
+ * But we are still holding ar->mutex, so the
+ * vif data [id, addr] is safe.
+ */
+ err = carl9170_mod_virtual_mac(ar, old_main_priv->id,
+ old_main->addr);
+ if (err)
+ goto unlock;
+ }
+
err = carl9170_init_interface(ar, vif);
if (err)
goto unlock;
--
1.7.10.4
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