mac80211: add PS flag to bss_conf

Currently, ps mode is indicated per device (rather than
per interface), which doesn't make a lot of sense.

Moreover, there are subtle bugs caused by the inability
to indicate ps change along with other changes
(e.g. when the AP deauth us, we'd like to indicate
CHANGED_PS | CHANGED_ASSOC, as changing PS before
notifying about disassociation will result in null-packets
being sent (if IEEE80211_HW_SUPPORTS_DYNAMIC_PS) while
the sta is already disconnected.)

Keep the current per-device notifications, and add
parallel per-vif notifications.

In order to keep it simple, the per-device ps and
the per-vif ps are orthogonal - the per-vif ps
configuration is determined only by the user
configuration (enable/disable) and the connection
state, and is not affected by other vifs state and
(temporary) dynamic_ps/offchannel operations
(unlike per-device ps).

Signed-off-by: Eliad Peller <eliad@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 3e2f03b..8e65ad9 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1203,6 +1203,7 @@
 void ieee80211_send_pspoll(struct ieee80211_local *local,
 			   struct ieee80211_sub_if_data *sdata);
 void ieee80211_recalc_ps(struct ieee80211_local *local, s32 latency);
+void ieee80211_recalc_ps_vif(struct ieee80211_sub_if_data *sdata);
 int ieee80211_max_network_latency(struct notifier_block *nb,
 				  unsigned long data, void *dummy);
 int ieee80211_set_arp_filter(struct ieee80211_sub_if_data *sdata);