mac80211: add TX prepare API

Some drivers require setup before being able to send
management frames in managed mode, in particular in
multi-channel cases.

Introduce API to allow the drivers to do such setup
while being able to sleep waiting for the setup to
finish in the device. This isn't possible inside the
TX call since that can't sleep.

A future patch may also restructure the TX retry to
wait for the driver to report the frame status, as
suggested by Arik in
http://mid.gmane.org/CA+XVXffKSEL6ZQPQ98x-zO-NL2=TNF1uN==mprRyUmAaRn254g@mail.gmail.com

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

3 files changed, 29 insertions, 0 deletions

diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 5042151a3325..df9203199102 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -852,4 +852,18 @@ static inline int drv_get_rssi(struct ieee80211_local *local,
 
         return ret;
 }
+
+static inline void drv_mgd_prepare_tx(struct ieee80211_local *local,
+                                      struct ieee80211_sub_if_data *sdata)
+{
+        might_sleep();
+
+        check_sdata_in_driver(sdata);
+        WARN_ON_ONCE(sdata->vif.type != NL80211_IFTYPE_STATION);
+
+        trace_drv_mgd_prepare_tx(local, sdata);
+        if (local->ops->mgd_prepare_tx)
+                local->ops->mgd_prepare_tx(&local->hw, &sdata->vif);
+        trace_drv_return_void(local);
+}
 #endif /* __MAC80211_DRIVER_OPS */
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index e9c0d1b68fc8..d563f7c55531 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -541,6 +541,8 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
                 memcpy(pos, assoc_data->ie + offset, noffset - offset);
         }
 
+        drv_mgd_prepare_tx(local, sdata);
+
         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
         ieee80211_tx_skb(sdata, skb);
 }
@@ -580,6 +582,9 @@ static void ieee80211_send_deauth_disassoc(struct ieee80211_sub_if_data *sdata,
                 if (!(ifmgd->flags & IEEE80211_STA_MFP_ENABLED))
                         IEEE80211_SKB_CB(skb)->flags |=
                                 IEEE80211_TX_INTFL_DONT_ENCRYPT;
+
+                drv_mgd_prepare_tx(local, sdata);
+
                 ieee80211_tx_skb(sdata, skb);
         }
 }
@@ -1756,6 +1761,7 @@ static void ieee80211_auth_challenge(struct ieee80211_sub_if_data *sdata,
         if (!elems.challenge)
                 return;
         auth_data->expected_transaction = 4;
+        drv_mgd_prepare_tx(sdata->local, sdata);
         ieee80211_send_auth(sdata, 3, auth_data->algorithm,
                             elems.challenge - 2, elems.challenge_len + 2,
                             auth_data->bss->bssid, auth_data->bss->bssid,
@@ -2641,6 +2647,8 @@ static int ieee80211_probe_auth(struct ieee80211_sub_if_data *sdata)
                 return -ETIMEDOUT;
         }
 
+        drv_mgd_prepare_tx(local, sdata);
+
         if (auth_data->bss->proberesp_ies) {
                 sdata_info(sdata, "send auth to %pM (try %d/%d)\n",
                            auth_data->bss->bssid, auth_data->tries,
diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h
index 2e60f4acd027..e1e9d10ec2e7 100644
--- a/net/mac80211/trace.h
+++ b/net/mac80211/trace.h
@@ -1244,6 +1244,13 @@ TRACE_EVENT(drv_get_rssi,
         )
 );
 
+DEFINE_EVENT(local_sdata_evt, drv_mgd_prepare_tx,
+        TP_PROTO(struct ieee80211_local *local,
+                 struct ieee80211_sub_if_data *sdata),
+
+        TP_ARGS(local, sdata)
+);
+
 /*
  * Tracing for API calls that drivers call.
  */