mac80211: add pre_channel_switch driver operation

Some drivers may need to prepare for a channel switch also when it is
initiated from the remote side (eg. station, P2P client).  To make
this possible, add a generic callback that can be called for all
interface types.

Signed-off-by: Luciano Coelho <luciano.coelho@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

4 files changed, 79 insertions, 8 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 3a04f2edd3c3..647a2f6eb7dc 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -3104,6 +3104,7 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
 {
         struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
         struct ieee80211_local *local = sdata->local;
+        struct ieee80211_channel_switch ch_switch;
         struct ieee80211_chanctx_conf *conf;
         struct ieee80211_chanctx *chanctx;
         int err, changed = 0;
@@ -3139,6 +3140,10 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
                 goto out;
         }
 
+        err = drv_pre_channel_switch(sdata, &ch_switch);
+        if (err)
+                goto out;
+
         err = ieee80211_vif_reserve_chanctx(sdata, &params->chandef,
                                             chanctx->mode,
                                             params->radar_required);
@@ -3152,6 +3157,12 @@ __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
                 goto out;
         }
 
+        ch_switch.timestamp = 0;
+        ch_switch.device_timestamp = 0;
+        ch_switch.block_tx = params->block_tx;
+        ch_switch.chandef = params->chandef;
+        ch_switch.count = params->count;
+
         err = ieee80211_set_csa_beacon(sdata, params, &changed);
         if (err) {
                 ieee80211_vif_unreserve_chanctx(sdata);
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 196d48c68134..5522672129ce 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -1196,6 +1196,24 @@ drv_channel_switch_beacon(struct ieee80211_sub_if_data *sdata,
         }
 }
 
+static inline int
+drv_pre_channel_switch(struct ieee80211_sub_if_data *sdata,
+                       struct ieee80211_channel_switch *ch_switch)
+{
+        struct ieee80211_local *local = sdata->local;
+        int ret = 0;
+
+        if (!check_sdata_in_driver(sdata))
+                return -EIO;
+
+        trace_drv_pre_channel_switch(local, sdata, ch_switch);
+        if (local->ops->pre_channel_switch)
+                ret = local->ops->pre_channel_switch(&local->hw, &sdata->vif,
+                                                     ch_switch);
+        trace_drv_return_int(local, ret);
+        return ret;
+}
+
 static inline int drv_join_ibss(struct ieee80211_local *local,
                                 struct ieee80211_sub_if_data *sdata)
 {
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index f2e048fa250c..d23d6d97e453 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1057,6 +1057,7 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
         struct ieee80211_chanctx *chanctx;
         enum ieee80211_band current_band;
         struct ieee80211_csa_ie csa_ie;
+        struct ieee80211_channel_switch ch_switch;
         int res;
 
         sdata_assert_lock(sdata);
@@ -1128,6 +1129,22 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
                 }
         }
 
+        ch_switch.timestamp = timestamp;
+        ch_switch.device_timestamp = device_timestamp;
+        ch_switch.block_tx = csa_ie.mode;
+        ch_switch.chandef = csa_ie.chandef;
+        ch_switch.count = csa_ie.count;
+
+        if (drv_pre_channel_switch(sdata, &ch_switch)) {
+                sdata_info(sdata,
+                           "preparing for channel switch failed, disconnecting\n");
+                ieee80211_queue_work(&local->hw,
+                                     &ifmgd->csa_connection_drop_work);
+                mutex_unlock(&local->chanctx_mtx);
+                mutex_unlock(&local->mtx);
+                return;
+        }
+
         res = ieee80211_vif_reserve_chanctx(sdata, &csa_ie.chandef,
                                             chanctx->mode, false);
         if (res) {
@@ -1153,14 +1170,6 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
 
         if (local->ops->channel_switch) {
                 /* use driver's channel switch callback */
-                struct ieee80211_channel_switch ch_switch = {
-                        .timestamp = timestamp,
-                        .device_timestamp = device_timestamp,
-                        .block_tx = csa_ie.mode,
-                        .chandef = csa_ie.chandef,
-                        .count = csa_ie.count,
-                };
-
                 drv_channel_switch(local, &ch_switch);
                 return;
         }
diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h
index 853c440218d4..30476d2c7302 100644
--- a/net/mac80211/trace.h
+++ b/net/mac80211/trace.h
@@ -2108,6 +2108,39 @@ TRACE_EVENT(drv_channel_switch_beacon,
         )
 );
 
+TRACE_EVENT(drv_pre_channel_switch,
+        TP_PROTO(struct ieee80211_local *local,
+                 struct ieee80211_sub_if_data *sdata,
+                 struct ieee80211_channel_switch *ch_switch),
+
+        TP_ARGS(local, sdata, ch_switch),
+
+        TP_STRUCT__entry(
+                LOCAL_ENTRY
+                VIF_ENTRY
+                CHANDEF_ENTRY
+                __field(u64, timestamp)
+                __field(bool, block_tx)
+                __field(u8, count)
+        ),
+
+        TP_fast_assign(
+                LOCAL_ASSIGN;
+                VIF_ASSIGN;
+                CHANDEF_ASSIGN(&ch_switch->chandef)
+                __entry->timestamp = ch_switch->timestamp;
+                __entry->block_tx = ch_switch->block_tx;
+                __entry->count = ch_switch->count;
+        ),
+
+        TP_printk(
+                LOCAL_PR_FMT VIF_PR_FMT " prepare channel switch to "
+                CHANDEF_PR_FMT  " count:%d block_tx:%d timestamp:%llu",
+                LOCAL_PR_ARG, VIF_PR_ARG, CHANDEF_PR_ARG, __entry->count,
+                __entry->block_tx, __entry->timestamp
+        )
+);
+
 
 #ifdef CONFIG_MAC80211_MESSAGE_TRACING
 #undef TRACE_SYSTEM