mac80211: make master netdev handling sane

Currently, almost every interface type has a 'bss' pointer
pointing to BSS information. This BSS information, however,
is for a _local_ BSS, not for the BSS we joined, so having
it on a STA mode interface makes little sense, but now they
have it pointing to the master device, which is an AP mode
virtual interface. However, except for some bitrate control
data, this pointer is only used in AP/VLAN modes (for power
saving stations.)

Overall, it is not necessary to even have the master netdev
be a valid virtual interface, and it doesn't have to be on
the list of interfaces either.

This patch changes the master netdev to be special, it now
 - no longer is on the list of virtual interfaces, which
   lets me remove a lot of tests for that
 - no longer has sub_if_data attached, since that isn't used

Additionally, this patch changes some vlan/ap mode handling
that is related to these 'bss' pointers described above (but
in the VLAN case they actually make sense because there they
point to the AP they belong to); it also adds some debugging
code to IEEE80211_DEV_TO_SUB_IF to validate it is not called
on the master netdev any more.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 21 insertions, 8 deletions

diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 47d2c1bbfcaa..f2ba653b9d69 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -320,7 +320,9 @@ int sta_info_insert(struct sta_info *sta)
         /* notify driver */
         if (local->ops->sta_notify) {
                 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
-                        sdata = sdata->u.vlan.ap;
+                        sdata = container_of(sdata->bss,
+                                             struct ieee80211_sub_if_data,
+                                             u.ap);
 
                 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
                                        STA_NOTIFY_ADD, sta->addr);
@@ -375,8 +377,10 @@ static inline void __bss_tim_clear(struct ieee80211_if_ap *bss, u16 aid)
 static void __sta_info_set_tim_bit(struct ieee80211_if_ap *bss,
                                    struct sta_info *sta)
 {
-        if (bss)
-                __bss_tim_set(bss, sta->aid);
+        BUG_ON(!bss);
+
+        __bss_tim_set(bss, sta->aid);
+
         if (sta->local->ops->set_tim) {
                 sta->local->tim_in_locked_section = true;
                 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 1);
@@ -388,6 +392,8 @@ void sta_info_set_tim_bit(struct sta_info *sta)
 {
         unsigned long flags;
 
+        BUG_ON(!sta->sdata->bss);
+
         spin_lock_irqsave(&sta->local->sta_lock, flags);
         __sta_info_set_tim_bit(sta->sdata->bss, sta);
         spin_unlock_irqrestore(&sta->local->sta_lock, flags);
@@ -396,8 +402,10 @@ void sta_info_set_tim_bit(struct sta_info *sta)
 static void __sta_info_clear_tim_bit(struct ieee80211_if_ap *bss,
                                      struct sta_info *sta)
 {
-        if (bss)
-                __bss_tim_clear(bss, sta->aid);
+        BUG_ON(!bss);
+
+        __bss_tim_clear(bss, sta->aid);
+
         if (sta->local->ops->set_tim) {
                 sta->local->tim_in_locked_section = true;
                 sta->local->ops->set_tim(local_to_hw(sta->local), sta->aid, 0);
@@ -409,6 +417,8 @@ void sta_info_clear_tim_bit(struct sta_info *sta)
 {
         unsigned long flags;
 
+        BUG_ON(!sta->sdata->bss);
+
         spin_lock_irqsave(&sta->local->sta_lock, flags);
         __sta_info_clear_tim_bit(sta->sdata->bss, sta);
         spin_unlock_irqrestore(&sta->local->sta_lock, flags);
@@ -437,8 +447,9 @@ void __sta_info_unlink(struct sta_info **sta)
         list_del(&(*sta)->list);
 
         if (test_and_clear_sta_flags(*sta, WLAN_STA_PS)) {
-                if (sdata->bss)
-                        atomic_dec(&sdata->bss->num_sta_ps);
+                BUG_ON(!sdata->bss);
+
+                atomic_dec(&sdata->bss->num_sta_ps);
                 __sta_info_clear_tim_bit(sdata->bss, *sta);
         }
 
@@ -446,7 +457,9 @@ void __sta_info_unlink(struct sta_info **sta)
 
         if (local->ops->sta_notify) {
                 if (sdata->vif.type == IEEE80211_IF_TYPE_VLAN)
-                        sdata = sdata->u.vlan.ap;
+                        sdata = container_of(sdata->bss,
+                                             struct ieee80211_sub_if_data,
+                                             u.ap);
 
                 local->ops->sta_notify(local_to_hw(local), &sdata->vif,
                                        STA_NOTIFY_REMOVE, (*sta)->addr);