mac80211: improve chanctx reservation lookup

Use a separate function to look for reservation
chanctx. For multi-interface/channel reservation
search sematics differ slightly.

The new routine allows reservations to be merged
with chanctx that are already reserved by other
interface(s).

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

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 0dfb04a..7303edd 100644 (file)
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -51,6 +51,93 @@ ieee80211_chanctx_reserved_chandef(struct ieee80211_local *local,
        return compat;
 }
 
+static const struct cfg80211_chan_def *
+ieee80211_chanctx_non_reserved_chandef(struct ieee80211_local *local,
+                                      struct ieee80211_chanctx *ctx,
+                                      const struct cfg80211_chan_def *compat)
+{
+       struct ieee80211_sub_if_data *sdata;
+
+       lockdep_assert_held(&local->chanctx_mtx);
+
+       list_for_each_entry(sdata, &ctx->assigned_vifs,
+                           assigned_chanctx_list) {
+               if (sdata->reserved_chanctx != NULL)
+                       continue;
+
+               if (!compat)
+                       compat = &sdata->vif.bss_conf.chandef;
+
+               compat = cfg80211_chandef_compatible(
+                               &sdata->vif.bss_conf.chandef, compat);
+               if (!compat)
+                       break;
+       }
+
+       return compat;
+}
+
+static const struct cfg80211_chan_def *
+ieee80211_chanctx_combined_chandef(struct ieee80211_local *local,
+                                  struct ieee80211_chanctx *ctx,
+                                  const struct cfg80211_chan_def *compat)
+{
+       lockdep_assert_held(&local->chanctx_mtx);
+
+       compat = ieee80211_chanctx_reserved_chandef(local, ctx, compat);
+       if (!compat)
+               return NULL;
+
+       compat = ieee80211_chanctx_non_reserved_chandef(local, ctx, compat);
+       if (!compat)
+               return NULL;
+
+       return compat;
+}
+
+static bool
+ieee80211_chanctx_can_reserve_chandef(struct ieee80211_local *local,
+                                     struct ieee80211_chanctx *ctx,
+                                     const struct cfg80211_chan_def *def)
+{
+       lockdep_assert_held(&local->chanctx_mtx);
+
+       if (ieee80211_chanctx_combined_chandef(local, ctx, def))
+               return true;
+
+       if (!list_empty(&ctx->reserved_vifs) &&
+           ieee80211_chanctx_reserved_chandef(local, ctx, def))
+               return true;
+
+       return false;
+}
+
+static struct ieee80211_chanctx *
+ieee80211_find_reservation_chanctx(struct ieee80211_local *local,
+                                  const struct cfg80211_chan_def *chandef,
+                                  enum ieee80211_chanctx_mode mode)
+{
+       struct ieee80211_chanctx *ctx;
+
+       lockdep_assert_held(&local->chanctx_mtx);
+
+       if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
+               return NULL;
+
+       list_for_each_entry(ctx, &local->chanctx_list, list) {
+               if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE)
+                       continue;
+
+               if (!ieee80211_chanctx_can_reserve_chandef(local, ctx,
+                                                          chandef))
+                       continue;
+
+               return ctx;
+       }
+
+       return NULL;
+}
+
 static enum nl80211_chan_width ieee80211_get_sta_bw(struct ieee80211_sta *sta)
 {
        switch (sta->bandwidth) {
@@ -771,8 +858,7 @@ int ieee80211_vif_reserve_chanctx(struct ieee80211_sub_if_data *sdata,
 
        curr_ctx = container_of(conf, struct ieee80211_chanctx, conf);
 
-       /* try to find another context with the chandef we want */
-       new_ctx = ieee80211_find_chanctx(local, chandef, mode);
+       new_ctx = ieee80211_find_reservation_chanctx(local, chandef, mode);
        if (!new_ctx) {
                if (curr_ctx->refcount == 1 &&
                    (local->hw.flags & IEEE80211_HW_CHANGE_RUNNING_CHANCTX)) {