mac80211: reuse channels for channel contexts

Reuse channels with compatible channel types. Some
channel types are compatible and can be used
concurrently.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 58 insertions, 1 deletions

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index ff3b29ec396a..1a8dee42e546 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -167,7 +167,17 @@ bool ieee80211_set_channel_type(struct ieee80211_local *local,
                 sdata->vif.bss_conf.channel_type = chantype;
 
         return true;
+}
+
+static void ieee80211_change_chantype(struct ieee80211_local *local,
+                                      struct ieee80211_chanctx *ctx,
+                                      enum nl80211_channel_type chantype)
+{
+        if (chantype == ctx->conf.channel_type)
+                return;
 
+        ctx->conf.channel_type = chantype;
+        drv_change_chanctx(local, ctx, IEEE80211_CHANCTX_CHANGE_CHANNEL_TYPE);
 }
 
 static struct ieee80211_chanctx *
@@ -177,6 +187,7 @@ ieee80211_find_chanctx(struct ieee80211_local *local,
                        enum ieee80211_chanctx_mode mode)
 {
         struct ieee80211_chanctx *ctx;
+        enum nl80211_channel_type compat_type;
 
         lockdep_assert_held(&local->chanctx_mtx);
 
@@ -186,13 +197,19 @@ ieee80211_find_chanctx(struct ieee80211_local *local,
                 return NULL;
 
         list_for_each_entry(ctx, &local->chanctx_list, list) {
+                compat_type = ctx->conf.channel_type;
+
                 if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
                         continue;
                 if (ctx->conf.channel != channel)
                         continue;
-                if (ctx->conf.channel_type != channel_type)
+                if (!ieee80211_channel_types_are_compatible(ctx->conf.channel_type,
+                                                            channel_type,
+                                                            &compat_type))
                         continue;
 
+                ieee80211_change_chantype(local, ctx, compat_type);
+
                 return ctx;
         }
 
@@ -260,6 +277,43 @@ static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
         return 0;
 }
 
+static enum nl80211_channel_type
+ieee80211_calc_chantype(struct ieee80211_local *local,
+                        struct ieee80211_chanctx *ctx)
+{
+        struct ieee80211_chanctx_conf *conf = &ctx->conf;
+        struct ieee80211_sub_if_data *sdata;
+        enum nl80211_channel_type result = NL80211_CHAN_NO_HT;
+
+        lockdep_assert_held(&local->chanctx_mtx);
+
+        rcu_read_lock();
+        list_for_each_entry_rcu(sdata, &local->interfaces, list) {
+                if (!ieee80211_sdata_running(sdata))
+                        continue;
+                if (rcu_access_pointer(sdata->vif.chanctx_conf) != conf)
+                        continue;
+
+                WARN_ON_ONCE(!ieee80211_channel_types_are_compatible(
+                                        sdata->vif.bss_conf.channel_type,
+                                        result, &result));
+        }
+        rcu_read_unlock();
+
+        return result;
+}
+
+static void ieee80211_recalc_chanctx_chantype(struct ieee80211_local *local,
+                                              struct ieee80211_chanctx *ctx)
+{
+        enum nl80211_channel_type chantype;
+
+        lockdep_assert_held(&local->chanctx_mtx);
+
+        chantype = ieee80211_calc_chantype(local, ctx);
+        ieee80211_change_chantype(local, ctx, chantype);
+}
+
 static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
                                            struct ieee80211_chanctx *ctx)
 {
@@ -271,6 +325,9 @@ static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
         rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);
 
         drv_unassign_vif_chanctx(local, sdata, ctx);
+
+        if (ctx->refcount > 0)
+                ieee80211_recalc_chanctx_chantype(sdata->local, ctx);
 }
 
 static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)