mac80211: move csa counters from sdata to beacon/presp

Having csa counters part of beacon and probe_resp
structures makes it easier to get rid of possible
races between setting a beacon and updating
counters on SMP systems by guaranteeing counters
are always consistent against given beacon struct.

While at it relax WARN_ON into WARN_ON_ONCE to
prevent spamming logs and racing.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
[remove pointless array check]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 44 insertions, 23 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index b6d73c14e1ae..af3eac482acd 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -554,7 +554,8 @@ static int ieee80211_set_monitor_channel(struct wiphy *wiphy,
 }
 
 static int ieee80211_set_probe_resp(struct ieee80211_sub_if_data *sdata,
-                                    const u8 *resp, size_t resp_len)
+                                    const u8 *resp, size_t resp_len,
+                                    const struct ieee80211_csa_settings *csa)
 {
         struct probe_resp *new, *old;
 
@@ -570,6 +571,11 @@ static int ieee80211_set_probe_resp(struct ieee80211_sub_if_data *sdata,
         new->len = resp_len;
         memcpy(new->data, resp, resp_len);
 
+        if (csa)
+                memcpy(new->csa_counter_offsets, csa->counter_offsets_presp,
+                       csa->n_counter_offsets_presp *
+                       sizeof(new->csa_counter_offsets[0]));
+
         rcu_assign_pointer(sdata->u.ap.probe_resp, new);
         if (old)
                 kfree_rcu(old, rcu_head);
@@ -578,7 +584,8 @@ static int ieee80211_set_probe_resp(struct ieee80211_sub_if_data *sdata,
 }
 
 static int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
-                                   struct cfg80211_beacon_data *params)
+                                   struct cfg80211_beacon_data *params,
+                                   const struct ieee80211_csa_settings *csa)
 {
         struct beacon_data *new, *old;
         int new_head_len, new_tail_len;
@@ -622,6 +629,13 @@ static int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
         new->head_len = new_head_len;
         new->tail_len = new_tail_len;
 
+        if (csa) {
+                new->csa_current_counter = csa->count;
+                memcpy(new->csa_counter_offsets, csa->counter_offsets_beacon,
+                       csa->n_counter_offsets_beacon *
+                       sizeof(new->csa_counter_offsets[0]));
+        }
+
         /* copy in head */
         if (params->head)
                 memcpy(new->head, params->head, new_head_len);
@@ -636,7 +650,7 @@ static int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata,
                         memcpy(new->tail, old->tail, new_tail_len);
 
         err = ieee80211_set_probe_resp(sdata, params->probe_resp,
-                                       params->probe_resp_len);
+                                       params->probe_resp_len, csa);
         if (err < 0)
                 return err;
         if (err == 0)
@@ -721,7 +735,7 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev,
                 sdata->vif.bss_conf.p2p_noa_attr.oppps_ctwindow |=
                                         IEEE80211_P2P_OPPPS_ENABLE_BIT;
 
-        err = ieee80211_assign_beacon(sdata, &params->beacon);
+        err = ieee80211_assign_beacon(sdata, &params->beacon, NULL);
         if (err < 0) {
                 ieee80211_vif_release_channel(sdata);
                 return err;
@@ -769,7 +783,7 @@ static int ieee80211_change_beacon(struct wiphy *wiphy, struct net_device *dev,
         if (!old)
                 return -ENOENT;
 
-        err = ieee80211_assign_beacon(sdata, params);
+        err = ieee80211_assign_beacon(sdata, params, NULL);
         if (err < 0)
                 return err;
         ieee80211_bss_info_change_notify(sdata, err);
@@ -2752,7 +2766,8 @@ static int ieee80211_set_after_csa_beacon(struct ieee80211_sub_if_data *sdata,
 
         switch (sdata->vif.type) {
         case NL80211_IFTYPE_AP:
-                err = ieee80211_assign_beacon(sdata, sdata->u.ap.next_beacon);
+                err = ieee80211_assign_beacon(sdata, sdata->u.ap.next_beacon,
+                                              NULL);
                 kfree(sdata->u.ap.next_beacon);
                 sdata->u.ap.next_beacon = NULL;
 
@@ -2855,6 +2870,7 @@ static int ieee80211_set_csa_beacon(struct ieee80211_sub_if_data *sdata,
                                     struct cfg80211_csa_settings *params,
                                     u32 *changed)
 {
+        struct ieee80211_csa_settings csa = {};
         int err;
 
         switch (sdata->vif.type) {
@@ -2889,20 +2905,13 @@ static int ieee80211_set_csa_beacon(struct ieee80211_sub_if_data *sdata,
                      IEEE80211_MAX_CSA_COUNTERS_NUM))
                         return -EINVAL;
 
-                /* make sure we don't have garbage in other counters */
-                memset(sdata->csa_counter_offset_beacon, 0,
-                       sizeof(sdata->csa_counter_offset_beacon));
-                memset(sdata->csa_counter_offset_presp, 0,
-                       sizeof(sdata->csa_counter_offset_presp));
-
-                memcpy(sdata->csa_counter_offset_beacon,
-                       params->counter_offsets_beacon,
-                       params->n_counter_offsets_beacon * sizeof(u16));
-                memcpy(sdata->csa_counter_offset_presp,
-                       params->counter_offsets_presp,
-                       params->n_counter_offsets_presp * sizeof(u16));
+                csa.counter_offsets_beacon = params->counter_offsets_beacon;
+                csa.counter_offsets_presp = params->counter_offsets_presp;
+                csa.n_counter_offsets_beacon = params->n_counter_offsets_beacon;
+                csa.n_counter_offsets_presp = params->n_counter_offsets_presp;
+                csa.count = params->count;
 
-                err = ieee80211_assign_beacon(sdata, &params->beacon_csa);
+                err = ieee80211_assign_beacon(sdata, &params->beacon_csa, &csa);
                 if (err < 0) {
                         kfree(sdata->u.ap.next_beacon);
                         return err;
@@ -3046,7 +3055,6 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
         sdata->csa_radar_required = params->radar_required;
         sdata->csa_chandef = params->chandef;
         sdata->csa_block_tx = params->block_tx;
-        sdata->csa_current_counter = params->count;
         sdata->vif.csa_active = true;
 
         if (sdata->csa_block_tx)
@@ -3194,10 +3202,23 @@ static int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
              sdata->vif.type == NL80211_IFTYPE_ADHOC) &&
             params->n_csa_offsets) {
                 int i;
-                u8 c = sdata->csa_current_counter;
+                struct beacon_data *beacon = NULL;
 
-                for (i = 0; i < params->n_csa_offsets; i++)
-                        data[params->csa_offsets[i]] = c;
+                rcu_read_lock();
+
+                if (sdata->vif.type == NL80211_IFTYPE_AP)
+                        beacon = rcu_dereference(sdata->u.ap.beacon);
+                else if (sdata->vif.type == NL80211_IFTYPE_ADHOC)
+                        beacon = rcu_dereference(sdata->u.ibss.presp);
+                else if (ieee80211_vif_is_mesh(&sdata->vif))
+                        beacon = rcu_dereference(sdata->u.mesh.beacon);
+
+                if (beacon)
+                        for (i = 0; i < params->n_csa_offsets; i++)
+                                data[params->csa_offsets[i]] =
+                                        beacon->csa_current_counter;
+
+                rcu_read_unlock();
         }
 
         IEEE80211_SKB_CB(skb)->flags = flags;