mac80211: prepare sta handling for MLO support

Currently in mac80211 each STA object is represented
using sta_info datastructure with the associated
STA specific information and drivers access ieee80211_sta
part of it.

With MLO (Multi Link Operation) support being added
in 802.11be standard, though the association is logically
with a single Multi Link capable STA, at the physical level
communication can happen via different advertised
links (uniquely identified by Channel, operating class,
BSSID) and hence the need to handle multiple link
STA parameters within a composite sta_info object
called the MLD STA. The different link STA part of
MLD STA are identified using the link address which can
be same or different as the MLD STA address and unique
link id based on the link vif.

To support extension of such a model, the sta_info
datastructure is modified to hold multiple link STA
objects with link specific params currently within
sta_info moved to this new structure. Similarly this is
done for ieee80211_sta as well which will be accessed
within mac80211 as well as by drivers, hence trivial
driver changes are expected to support this.

For current non MLO supported drivers, only one link STA
is present and link information is accessed via 'deflink'
member.

For MLO drivers, we still need to define the APIs etc. to
get the correct link ID and access the correct part of
the station info.

Currently in mac80211, all link STA info are accessed directly
via deflink. These will be updated to access via link pointers
indexed by link id with MLO support patches, with link id
being 0 for non MLO supported cases.

Except for couple of macro related changes, below spatch takes
care of updating mac80211 and driver code to access to the
link STA info via deflink.

  @ieee80211_sta@
  struct ieee80211_sta *s;
  struct sta_info *si;
  identifier var = {supp_rates, ht_cap, vht_cap, he_cap, he_6ghz_capa, eht_cap, rx_nss, bandwidth, txpwr};
  @@

  (
    s->
  -    var
  +    deflink.var
  |
   si->sta.
  -    var
  +    deflink.var
  )

  @sta_info@
  struct sta_info *si;
  identifier var = {gtk, pcpu_rx_stats, rx_stats, rx_stats_avg, status_stats, tx_stats, cur_max_bandwidth};
  @@

  (
    si->
  -    var
  +    deflink.var
  )

Signed-off-by: Sriram R <quic_srirrama@quicinc.com>
Link: https://lore.kernel.org/r/1649086883-13246-1-git-send-email-quic_srirrama@quicinc.com
[remove MLO-drivers notes from commit message, not clear yet; run spatch]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index f695fc80088b..0fcf8aebedc4 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -476,7 +476,7 @@ static int ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
 			    !(new->conf.flags & IEEE80211_KEY_FLAG_NO_AUTO_TX))
 				_ieee80211_set_tx_key(new, true);
 		} else {
-			rcu_assign_pointer(sta->gtk[idx], new);
+			rcu_assign_pointer(sta->deflink.gtk[idx], new);
 		}
 		/* Only needed for transition from no key -> key.
 		 * Still triggers unnecessary when using Extended Key ID
@@ -826,7 +826,8 @@ int ieee80211_key_link(struct ieee80211_key *key,
 		    (old_key && old_key->conf.cipher != key->conf.cipher))
 			goto out;
 	} else if (sta) {
-		old_key = key_mtx_dereference(sdata->local, sta->gtk[idx]);
+		old_key = key_mtx_dereference(sdata->local,
+					      sta->deflink.gtk[idx]);
 	} else {
 		old_key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
 	}
@@ -1076,8 +1077,8 @@ void ieee80211_free_sta_keys(struct ieee80211_local *local,
 	int i;
 
 	mutex_lock(&local->key_mtx);
-	for (i = 0; i < ARRAY_SIZE(sta->gtk); i++) {
-		key = key_mtx_dereference(local, sta->gtk[i]);
+	for (i = 0; i < ARRAY_SIZE(sta->deflink.gtk); i++) {
+		key = key_mtx_dereference(local, sta->deflink.gtk[i]);
 		if (!key)
 			continue;
 		ieee80211_key_replace(key->sdata, key->sta,