mac80211: Update beacon's timing and DTIM count on every beacon

Beacon's timestamp, device system time associated with this beacon and
DTIM count parameters are not updated in the associated vif context
if the latest beacon's content is identical to the previously received.
It make sense to update these changing parameters on every beacon so the
driver can get most updated values. This may be necessary, for example,
to avoid either beacons' drift effect or device time stamp overrun.
IMPORTANT: Three sync_* parameters - sync_ts, sync_device_ts and
sync_dtim_count would possibly be out of sync by the time the driver will
use them. The synchronized view is currently guaranteed only in certain
callbacks.

Signed-off-by: Alexander Bondar <alexander.bondar@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 20 insertions, 12 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 10ac6324c1d0..cf3ae9348a9d 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -3419,6 +3419,26 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
         if (ifmgd->csa_waiting_bcn)
                 ieee80211_chswitch_post_beacon(sdata);
 
+        /*
+         * Update beacon timing and dtim count on every beacon appearance. This
+         * will allow the driver to use the most updated values. Do it before
+         * comparing this one with last received beacon.
+         * IMPORTANT: These parameters would possibly be out of sync by the time
+         * the driver will use them. The synchronized view is currently
+         * guaranteed only in certain callbacks.
+         */
+        if (local->hw.flags & IEEE80211_HW_TIMING_BEACON_ONLY) {
+                sdata->vif.bss_conf.sync_tsf =
+                        le64_to_cpu(mgmt->u.beacon.timestamp);
+                sdata->vif.bss_conf.sync_device_ts =
+                        rx_status->device_timestamp;
+                if (elems.tim)
+                        sdata->vif.bss_conf.sync_dtim_count =
+                                elems.tim->dtim_count;
+                else
+                        sdata->vif.bss_conf.sync_dtim_count = 0;
+        }
+
         if (ncrc == ifmgd->beacon_crc && ifmgd->beacon_crc_valid)
                 return;
         ifmgd->beacon_crc = ncrc;
@@ -3446,18 +3466,6 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
                 else
                         bss_conf->dtim_period = 1;
 
-                if (local->hw.flags & IEEE80211_HW_TIMING_BEACON_ONLY) {
-                        sdata->vif.bss_conf.sync_tsf =
-                                le64_to_cpu(mgmt->u.beacon.timestamp);
-                        sdata->vif.bss_conf.sync_device_ts =
-                                rx_status->device_timestamp;
-                        if (elems.tim)
-                                sdata->vif.bss_conf.sync_dtim_count =
-                                        elems.tim->dtim_count;
-                        else
-                                sdata->vif.bss_conf.sync_dtim_count = 0;
-                }
-
                 changed |= BSS_CHANGED_BEACON_INFO;
                 ifmgd->have_beacon = true;