mac80211: mesh: only get tsf if we need it

[linux-2.6-microblaze.git] / net / mac80211 / mesh_sync.c

diff --git a/net/mac80211/mesh_sync.c b/net/mac80211/mesh_sync.c
index 05a256b..d1cf2d5 100644 (file)
--- a/net/mac80211/mesh_sync.c
+++ b/net/mac80211/mesh_sync.c
@@ -92,12 +92,20 @@ static void mesh_sync_offset_rx_bcn_presp(struct ieee80211_sub_if_data *sdata,
        if (stype != IEEE80211_STYPE_BEACON)
                return;
 
-       /* The current tsf is a first approximation for the timestamp
-        * for the received beacon.  Further down we try to get a
-        * better value from the rx_status->mactime field if
-        * available. Also we have to call drv_get_tsf() before
-        * entering the rcu-read section.*/
-       t_r = drv_get_tsf(local, sdata);
+       /*
+        * Get time when timestamp field was received.  If we don't
+        * have rx timestamps, then use current tsf as an approximation.
+        * drv_get_tsf() must be called before entering the rcu-read
+        * section.
+        */
+       if (ieee80211_have_rx_timestamp(rx_status))
+               t_r = ieee80211_calculate_rx_timestamp(local, rx_status,
+                                                      24 + 12 +
+                                                      elems->total_len +
+                                                      FCS_LEN,
+                                                      24);
+       else
+               t_r = drv_get_tsf(local, sdata);
 
        rcu_read_lock();
        sta = sta_info_get(sdata, mgmt->sa);
@@ -117,14 +125,6 @@ static void mesh_sync_offset_rx_bcn_presp(struct ieee80211_sub_if_data *sdata,
                goto no_sync;
        }
 
-       if (ieee80211_have_rx_timestamp(rx_status))
-               /* time when timestamp field was received */
-               t_r = ieee80211_calculate_rx_timestamp(local, rx_status,
-                                                      24 + 12 +
-                                                      elems->total_len +
-                                                      FCS_LEN,
-                                                      24);
-
        /* Timing offset calculation (see 13.13.2.2.2) */
        t_t = le64_to_cpu(mgmt->u.beacon.timestamp);
        sta->t_offset = t_t - t_r;