mac80211: force use_short_slot=true for 5GHz

Normally 5GHz does not have a concept of long vs short slot time,
however the slot time that it ends up using is the same as for 2.4 GHZ
and use_short_slot == true
Because of that, it makes more sense to force use_short_slot = true
whenever 5 GHz is being used, so that this particular check does not
have to be in every single driver that uses this flag.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 9 insertions, 0 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 8286df5822d5..b0102c538b30 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1085,6 +1085,13 @@ static int ieee80211_change_bss(struct wiphy *wiphy,
                         params->use_short_preamble;
                 changed |= BSS_CHANGED_ERP_PREAMBLE;
         }
+
+        if (!sdata->vif.bss_conf.use_short_slot &&
+            sdata->local->hw.conf.channel->band == IEEE80211_BAND_5GHZ) {
+                sdata->vif.bss_conf.use_short_slot = true;
+                changed |= BSS_CHANGED_ERP_SLOT;
+        }
+
         if (params->use_short_slot_time >= 0) {
                 sdata->vif.bss_conf.use_short_slot =
                         params->use_short_slot_time;
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 2746391248d3..a82564e73d91 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -670,6 +670,8 @@ static u32 ieee80211_handle_bss_capability(struct ieee80211_sub_if_data *sdata,
         }
 
         use_short_slot = !!(capab & WLAN_CAPABILITY_SHORT_SLOT_TIME);
+        if (sdata->local->hw.conf.channel->band == IEEE80211_BAND_5GHZ)
+                use_short_slot = true;
 
         if (use_protection != bss_conf->use_cts_prot) {
                 bss_conf->use_cts_prot = use_protection;