mac80211: track reserved vifs in chanctx

This can be useful. Provides a more straghtforward
way to iterate over interfaces taking part in
chanctx reservation and allows tracking chanctx
usage explicitly.

The structure is protected by local->chanctx_mtx.

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

3 files changed, 13 insertions, 4 deletions

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 504526c97867..79eac96d9e5f 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -277,6 +277,7 @@ ieee80211_new_chanctx(struct ieee80211_local *local,
                 return ERR_PTR(-ENOMEM);
 
         INIT_LIST_HEAD(&ctx->assigned_vifs);
+        INIT_LIST_HEAD(&ctx->reserved_vifs);
         ctx->conf.def = *chandef;
         ctx->conf.rx_chains_static = 1;
         ctx->conf.rx_chains_dynamic = 1;
@@ -731,16 +732,19 @@ void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata,
 
 int ieee80211_vif_unreserve_chanctx(struct ieee80211_sub_if_data *sdata)
 {
+        struct ieee80211_chanctx *ctx = sdata->reserved_chanctx;
+
         lockdep_assert_held(&sdata->local->chanctx_mtx);
 
-        if (WARN_ON(!sdata->reserved_chanctx))
+        if (WARN_ON(!ctx))
                 return -EINVAL;
 
-        if (--sdata->reserved_chanctx->refcount == 0)
-                ieee80211_free_chanctx(sdata->local, sdata->reserved_chanctx);
-
+        list_del(&sdata->reserved_chanctx_list);
         sdata->reserved_chanctx = NULL;
 
+        if (--ctx->refcount == 0)
+                ieee80211_free_chanctx(sdata->local, ctx);
+
         return 0;
 }
 
@@ -788,6 +792,7 @@ int ieee80211_vif_reserve_chanctx(struct ieee80211_sub_if_data *sdata,
                 }
         }
 
+        list_add(&sdata->reserved_chanctx_list, &new_ctx->reserved_vifs);
         new_ctx->refcount++;
         sdata->reserved_chanctx = new_ctx;
         sdata->reserved_chandef = *chandef;
@@ -837,6 +842,7 @@ int ieee80211_vif_use_reserved_context(struct ieee80211_sub_if_data *sdata,
         ctx->refcount--;
         sdata->reserved_chanctx = NULL;
         sdata->radar_required = sdata->reserved_radar_required;
+        list_del(&sdata->reserved_chanctx_list);
 
         if (old_ctx == ctx) {
                 /* This is our own context, just change it */
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 3b3b45a21501..3eaf6d7fad52 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -692,6 +692,7 @@ struct ieee80211_chanctx {
         struct rcu_head rcu_head;
 
         struct list_head assigned_vifs;
+        struct list_head reserved_vifs;
 
         enum ieee80211_chanctx_mode mode;
         int refcount;
@@ -759,6 +760,7 @@ struct ieee80211_sub_if_data {
         struct cfg80211_chan_def csa_chandef;
 
         struct list_head assigned_chanctx_list; /* protected by chanctx_mtx */
+        struct list_head reserved_chanctx_list; /* protected by chanctx_mtx */
 
         /* context reservation -- protected with chanctx_mtx */
         struct ieee80211_chanctx *reserved_chanctx;
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index a562d0f489e1..e91569d887e3 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1292,6 +1292,7 @@ static void ieee80211_setup_sdata(struct ieee80211_sub_if_data *sdata,
         INIT_WORK(&sdata->recalc_smps, ieee80211_recalc_smps_work);
         INIT_WORK(&sdata->csa_finalize_work, ieee80211_csa_finalize_work);
         INIT_LIST_HEAD(&sdata->assigned_chanctx_list);
+        INIT_LIST_HEAD(&sdata->reserved_chanctx_list);
 
         switch (type) {
         case NL80211_IFTYPE_P2P_GO: