mac80211: improve HT channel handling

Currently, when one interface switches HT mode,
all others will follow along. This is clearly
undesirable, since the new one might switch to
no-HT while another one is operating in HT.

Address this issue by keeping track of the HT
mode per interface, and allowing only changes
that are compatible, i.e. switching into HT40+
is not possible when another interface is in
HT40-, in that case the second one needs to
fall back to HT20.

Also, to allow drivers to know what's going on,
store the per-interface HT mode (channel type)
in the virtual interface's bss_conf.

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

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 62a739f..bdce71a 100644 (file)
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -651,17 +651,17 @@ static void mac80211_hwsim_beacon(unsigned long arg)
        add_timer(&data->beacon_timer);
 }
 
+static const char *hwsim_chantypes[] = {
+       [NL80211_CHAN_NO_HT] = "noht",
+       [NL80211_CHAN_HT20] = "ht20",
+       [NL80211_CHAN_HT40MINUS] = "ht40-",
+       [NL80211_CHAN_HT40PLUS] = "ht40+",
+};
 
 static int mac80211_hwsim_config(struct ieee80211_hw *hw, u32 changed)
 {
        struct mac80211_hwsim_data *data = hw->priv;
        struct ieee80211_conf *conf = &hw->conf;
-       static const char *chantypes[4] = {
-               [NL80211_CHAN_NO_HT] = "noht",
-               [NL80211_CHAN_HT20] = "ht20",
-               [NL80211_CHAN_HT40MINUS] = "ht40-",
-               [NL80211_CHAN_HT40PLUS] = "ht40+",
-       };
        static const char *smps_modes[IEEE80211_SMPS_NUM_MODES] = {
                [IEEE80211_SMPS_AUTOMATIC] = "auto",
                [IEEE80211_SMPS_OFF] = "off",
@@ -672,7 +672,7 @@ static int mac80211_hwsim_config(struct ieee80211_hw *hw, u32 changed)
        printk(KERN_DEBUG "%s:%s (freq=%d/%s idle=%d ps=%d smps=%s)\n",
               wiphy_name(hw->wiphy), __func__,
               conf->channel->center_freq,
-              chantypes[conf->channel_type],
+              hwsim_chantypes[conf->channel_type],
               !!(conf->flags & IEEE80211_CONF_IDLE),
               !!(conf->flags & IEEE80211_CONF_PS),
               smps_modes[conf->smps_mode]);
@@ -760,9 +760,10 @@ static void mac80211_hwsim_bss_info_changed(struct ieee80211_hw *hw,
        }
 
        if (changed & BSS_CHANGED_HT) {
-               printk(KERN_DEBUG "  %s: HT: op_mode=0x%x\n",
+               printk(KERN_DEBUG "  %s: HT: op_mode=0x%x, chantype=%s\n",
                       wiphy_name(hw->wiphy),
-                      info->ht_operation_mode);
+                      info->ht_operation_mode,
+                      hwsim_chantypes[info->channel_type]);
        }
 
        if (changed & BSS_CHANGED_BASIC_RATES) {

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 0528615..9448a5b 100644 (file)
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -191,6 +191,9 @@ enum ieee80211_bss_change {
  *     the current band.
  * @bssid: The BSSID for this BSS
  * @enable_beacon: whether beaconing should be enabled or not
+ * @channel_type: Channel type for this BSS -- the hardware might be
+ *     configured for HT40+ while this BSS only uses no-HT, for
+ *     example.
  * @ht_operation_mode: HT operation mode (like in &struct ieee80211_ht_info).
  *     This field is only valid when the channel type is one of the HT types.
  * @cqm_rssi_thold: Connection quality monitor RSSI threshold, a zero value
@@ -215,6 +218,7 @@ struct ieee80211_bss_conf {
        u16 ht_operation_mode;
        s32 cqm_rssi_thold;
        u32 cqm_rssi_hyst;
+       enum nl80211_channel_type channel_type;
 };
 
 /**

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 414b7dd..ab166c6 100644 (file)
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1166,23 +1166,34 @@ static int ieee80211_set_channel(struct wiphy *wiphy,
                                 enum nl80211_channel_type channel_type)
 {
        struct ieee80211_local *local = wiphy_priv(wiphy);
+       struct ieee80211_sub_if_data *sdata = NULL;
+
+       if (netdev)
+               sdata = IEEE80211_DEV_TO_SUB_IF(netdev);
 
        switch (ieee80211_get_channel_mode(local, NULL)) {
        case CHAN_MODE_HOPPING:
                return -EBUSY;
        case CHAN_MODE_FIXED:
-               if (local->oper_channel == chan &&
-                   local->oper_channel_type == channel_type)
+               if (local->oper_channel != chan)
+                       return -EBUSY;
+               if (!sdata && local->_oper_channel_type == channel_type)
                        return 0;
-               return -EBUSY;
+               break;
        case CHAN_MODE_UNDEFINED:
                break;
        }
 
        local->oper_channel = chan;
-       local->oper_channel_type = channel_type;
 
-       return ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+       if (!ieee80211_set_channel_type(local, sdata, channel_type))
+               return -EBUSY;
+
+       ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+       if (sdata && sdata->vif.type != NL80211_IFTYPE_MONITOR)
+               ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_HT);
+
+       return 0;
 }
 
 #ifdef CONFIG_PM
@@ -1406,7 +1417,7 @@ int __ieee80211_request_smps(struct ieee80211_sub_if_data *sdata,
         * association, there's no need to send an action frame.
         */
        if (!sdata->u.mgd.associated ||
-           sdata->local->oper_channel_type == NL80211_CHAN_NO_HT) {
+           sdata->vif.bss_conf.channel_type == NL80211_CHAN_NO_HT) {
                mutex_lock(&sdata->local->iflist_mtx);
                ieee80211_recalc_smps(sdata->local, sdata);
                mutex_unlock(&sdata->local->iflist_mtx);

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 08f3832..5d218c5 100644 (file)
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -2,6 +2,7 @@
  * mac80211 - channel management
  */
 
+#include <linux/nl80211.h>
 #include "ieee80211_i.h"
 
 enum ieee80211_chan_mode
@@ -55,3 +56,72 @@ ieee80211_get_channel_mode(struct ieee80211_local *local,
 
        return mode;
 }
+
+bool ieee80211_set_channel_type(struct ieee80211_local *local,
+                               struct ieee80211_sub_if_data *sdata,
+                               enum nl80211_channel_type chantype)
+{
+       struct ieee80211_sub_if_data *tmp;
+       enum nl80211_channel_type superchan = NL80211_CHAN_NO_HT;
+       bool result;
+
+       mutex_lock(&local->iflist_mtx);
+
+       list_for_each_entry(tmp, &local->interfaces, list) {
+               if (tmp == sdata)
+                       continue;
+
+               if (!ieee80211_sdata_running(tmp))
+                       continue;
+
+               switch (tmp->vif.bss_conf.channel_type) {
+               case NL80211_CHAN_NO_HT:
+               case NL80211_CHAN_HT20:
+                       superchan = tmp->vif.bss_conf.channel_type;
+                       break;
+               case NL80211_CHAN_HT40PLUS:
+                       WARN_ON(superchan == NL80211_CHAN_HT40MINUS);
+                       superchan = NL80211_CHAN_HT40PLUS;
+                       break;
+               case NL80211_CHAN_HT40MINUS:
+                       WARN_ON(superchan == NL80211_CHAN_HT40PLUS);
+                       superchan = NL80211_CHAN_HT40MINUS;
+                       break;
+               }
+       }
+
+       switch (superchan) {
+       case NL80211_CHAN_NO_HT:
+       case NL80211_CHAN_HT20:
+               /*
+                * allow any change that doesn't go to no-HT
+                * (if it already is no-HT no change is needed)
+                */
+               if (chantype == NL80211_CHAN_NO_HT)
+                       break;
+               superchan = chantype;
+               break;
+       case NL80211_CHAN_HT40PLUS:
+       case NL80211_CHAN_HT40MINUS:
+               /* allow smaller bandwidth and same */
+               if (chantype == NL80211_CHAN_NO_HT)
+                       break;
+               if (chantype == NL80211_CHAN_HT20)
+                       break;
+               if (superchan == chantype)
+                       break;
+               result = false;
+               goto out;
+       }
+
+       local->_oper_channel_type = superchan;
+
+       if (sdata)
+               sdata->vif.bss_conf.channel_type = chantype;
+
+       result = true;
+ out:
+       mutex_unlock(&local->iflist_mtx);
+
+       return result;
+}

diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
index d5855ae..36745f4 100644 (file)
--- a/net/mac80211/ibss.c
+++ b/net/mac80211/ibss.c
@@ -102,7 +102,7 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
        sdata->drop_unencrypted = capability & WLAN_CAPABILITY_PRIVACY ? 1 : 0;
 
        local->oper_channel = chan;
-       local->oper_channel_type = NL80211_CHAN_NO_HT;
+       WARN_ON(!ieee80211_set_channel_type(local, sdata, NL80211_CHAN_NO_HT));
        ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 
        sband = local->hw.wiphy->bands[chan->band];
@@ -910,7 +910,8 @@ int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
        /* fix ourselves to that channel now already */
        if (params->channel_fixed) {
                sdata->local->oper_channel = params->channel;
-               sdata->local->oper_channel_type = NL80211_CHAN_NO_HT;
+               WARN_ON(!ieee80211_set_channel_type(sdata->local, sdata,
+                                                   NL80211_CHAN_NO_HT));
        }
 
        if (params->ie) {

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 359edff..69e7f41 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -768,7 +768,7 @@ struct ieee80211_local {
        enum mac80211_scan_state next_scan_state;
        struct delayed_work scan_work;
        struct ieee80211_sub_if_data *scan_sdata;
-       enum nl80211_channel_type oper_channel_type;
+       enum nl80211_channel_type _oper_channel_type;
        struct ieee80211_channel *oper_channel, *csa_channel;
 
        /* Temporary remain-on-channel for off-channel operations */
@@ -1239,6 +1239,9 @@ enum ieee80211_chan_mode {
 enum ieee80211_chan_mode
 ieee80211_get_channel_mode(struct ieee80211_local *local,
                           struct ieee80211_sub_if_data *ignore);
+bool ieee80211_set_channel_type(struct ieee80211_local *local,
+                               struct ieee80211_sub_if_data *sdata,
+                               enum nl80211_channel_type chantype);
 
 #ifdef CONFIG_MAC80211_NOINLINE
 #define debug_noinline noinline

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 353b6b4..d763d76 100644 (file)
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -111,7 +111,7 @@ int ieee80211_hw_config(struct ieee80211_local *local, u32 changed)
                channel_type = local->tmp_channel_type;
        } else {
                chan = local->oper_channel;
-               channel_type = local->oper_channel_type;
+               channel_type = local->_oper_channel_type;
        }
 
        if (chan != local->hw.conf.channel ||

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 17cb8ae..6e149b4 100644 (file)
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -136,11 +136,14 @@ static u32 ieee80211_enable_ht(struct ieee80211_sub_if_data *sdata,
        struct sta_info *sta;
        u32 changed = 0;
        u16 ht_opmode;
-       bool enable_ht = true, ht_changed;
+       bool enable_ht = true;
+       enum nl80211_channel_type prev_chantype;
        enum nl80211_channel_type channel_type = NL80211_CHAN_NO_HT;
 
        sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 
+       prev_chantype = sdata->vif.bss_conf.channel_type;
+
        /* HT is not supported */
        if (!sband->ht_cap.ht_supported)
                enable_ht = false;
@@ -171,38 +174,37 @@ static u32 ieee80211_enable_ht(struct ieee80211_sub_if_data *sdata,
                }
        }
 
-       ht_changed = conf_is_ht(&local->hw.conf) != enable_ht ||
-                    channel_type != local->hw.conf.channel_type;
-
        if (local->tmp_channel)
                local->tmp_channel_type = channel_type;
-       local->oper_channel_type = channel_type;
 
-       if (ht_changed) {
-                /* channel_type change automatically detected */
-               ieee80211_hw_config(local, 0);
+       if (!ieee80211_set_channel_type(local, sdata, channel_type)) {
+               /* can only fail due to HT40+/- mismatch */
+               channel_type = NL80211_CHAN_HT20;
+               WARN_ON(!ieee80211_set_channel_type(local, sdata, channel_type));
+       }
 
+       /* channel_type change automatically detected */
+       ieee80211_hw_config(local, 0);
+
+       if (prev_chantype != channel_type) {
                rcu_read_lock();
                sta = sta_info_get(sdata, bssid);
                if (sta)
                        rate_control_rate_update(local, sband, sta,
                                                 IEEE80211_RC_HT_CHANGED,
-                                                local->oper_channel_type);
+                                                channel_type);
                rcu_read_unlock();
-        }
-
-       /* disable HT */
-       if (!enable_ht)
-               return 0;
+       }
 
        ht_opmode = le16_to_cpu(hti->operation_mode);
 
        /* if bss configuration changed store the new one */
-       if (!sdata->ht_opmode_valid ||
-           sdata->vif.bss_conf.ht_operation_mode != ht_opmode) {
+       if (sdata->ht_opmode_valid != enable_ht ||
+           sdata->vif.bss_conf.ht_operation_mode != ht_opmode ||
+           prev_chantype != channel_type) {
                changed |= BSS_CHANGED_HT;
                sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
-               sdata->ht_opmode_valid = true;
+               sdata->ht_opmode_valid = enable_ht;
        }
 
        return changed;
@@ -865,7 +867,7 @@ static void ieee80211_set_disassoc(struct ieee80211_sub_if_data *sdata,
        ieee80211_set_wmm_default(sdata);
 
        /* channel(_type) changes are handled by ieee80211_hw_config */
-       local->oper_channel_type = NL80211_CHAN_NO_HT;
+       WARN_ON(!ieee80211_set_channel_type(local, sdata, NL80211_CHAN_NO_HT));
 
        /* on the next assoc, re-program HT parameters */
        sdata->ht_opmode_valid = false;
@@ -882,8 +884,8 @@ static void ieee80211_set_disassoc(struct ieee80211_sub_if_data *sdata,
 
        ieee80211_hw_config(local, config_changed);
 
-       /* And the BSSID changed -- not very interesting here */
-       changed |= BSS_CHANGED_BSSID;
+       /* The BSSID (not really interesting) and HT changed */
+       changed |= BSS_CHANGED_BSSID | BSS_CHANGED_HT;
        ieee80211_bss_info_change_notify(sdata, changed);
 
        if (remove_sta)
@@ -2265,7 +2267,7 @@ int ieee80211_mgd_action(struct ieee80211_sub_if_data *sdata,
        if ((chan != local->tmp_channel ||
             channel_type != local->tmp_channel_type) &&
            (chan != local->oper_channel ||
-            channel_type != local->oper_channel_type))
+            channel_type != local->_oper_channel_type))
                return -EBUSY;
 
        skb = dev_alloc_skb(local->hw.extra_tx_headroom + len);