1 files changed, 86 insertions, 68 deletions

diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 5171a9581631..fb274db77e3c 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -249,12 +249,12 @@ static bool ieee80211_prep_hw_scan(struct ieee80211_local *local)
         return true;
 }
 
-static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
+static bool __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted,
+                                       bool was_hw_scan)
 {
         struct ieee80211_local *local = hw_to_local(hw);
-        bool was_hw_scan;
 
-        mutex_lock(&local->mtx);
+        lockdep_assert_held(&local->mtx);
 
         /*
          * It's ok to abort a not-yet-running scan (that
@@ -265,17 +265,13 @@ static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
         if (WARN_ON(!local->scanning && !aborted))
                 aborted = true;
 
-        if (WARN_ON(!local->scan_req)) {
-                mutex_unlock(&local->mtx);
-                return;
-        }
+        if (WARN_ON(!local->scan_req))
+                return false;
 
-        was_hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
         if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {
-                ieee80211_queue_delayed_work(&local->hw,
-                                             &local->scan_work, 0);
-                mutex_unlock(&local->mtx);
-                return;
+                int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);
+                if (rc == 0)
+                        return false;
         }
 
         kfree(local->hw_scan_req);
@@ -289,23 +285,25 @@ static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
         local->scanning = 0;
         local->scan_channel = NULL;
 
-        /* we only have to protect scan_req and hw/sw scan */
-        mutex_unlock(&local->mtx);
-
-        ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
-        if (was_hw_scan)
-                goto done;
-
-        ieee80211_configure_filter(local);
+        return true;
+}
 
-        drv_sw_scan_complete(local);
+static void __ieee80211_scan_completed_finish(struct ieee80211_hw *hw,
+                                              bool was_hw_scan)
+{
+        struct ieee80211_local *local = hw_to_local(hw);
 
-        ieee80211_offchannel_return(local, true);
+        ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+        if (!was_hw_scan) {
+                ieee80211_configure_filter(local);
+                drv_sw_scan_complete(local);
+                ieee80211_offchannel_return(local, true);
+        }
 
- done:
         mutex_lock(&local->mtx);
         ieee80211_recalc_idle(local);
         mutex_unlock(&local->mtx);
+
         ieee80211_mlme_notify_scan_completed(local);
         ieee80211_ibss_notify_scan_completed(local);
         ieee80211_mesh_notify_scan_completed(local);
@@ -366,6 +364,8 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
         struct ieee80211_local *local = sdata->local;
         int rc;
 
+        lockdep_assert_held(&local->mtx);
+
         if (local->scan_req)
                 return -EBUSY;
 
@@ -447,8 +447,8 @@ ieee80211_scan_get_channel_time(struct ieee80211_channel *chan)
         return IEEE80211_PROBE_DELAY + IEEE80211_CHANNEL_TIME;
 }
 
-static int ieee80211_scan_state_decision(struct ieee80211_local *local,
-                                         unsigned long *next_delay)
+static void ieee80211_scan_state_decision(struct ieee80211_local *local,
+                                          unsigned long *next_delay)
 {
         bool associated = false;
         bool tx_empty = true;
@@ -458,12 +458,6 @@ static int ieee80211_scan_state_decision(struct ieee80211_local *local,
         struct ieee80211_sub_if_data *sdata;
         struct ieee80211_channel *next_chan;
 
-        /* if no more bands/channels left, complete scan and advance to the idle state */
-        if (local->scan_channel_idx >= local->scan_req->n_channels) {
-                __ieee80211_scan_completed(&local->hw, false);
-                return 1;
-        }
-
         /*
          * check if at least one STA interface is associated,
          * check if at least one STA interface has pending tx frames
@@ -535,7 +529,6 @@ static int ieee80211_scan_state_decision(struct ieee80211_local *local,
         }
 
         *next_delay = 0;
-        return 0;
 }
 
 static void ieee80211_scan_state_leave_oper_channel(struct ieee80211_local *local,
@@ -651,28 +644,17 @@ void ieee80211_scan_work(struct work_struct *work)
                 container_of(work, struct ieee80211_local, scan_work.work);
         struct ieee80211_sub_if_data *sdata = local->scan_sdata;
         unsigned long next_delay = 0;
+        bool aborted, hw_scan, finish;
 
-        if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
-                bool aborted;
+        mutex_lock(&local->mtx);
 
+        if (test_and_clear_bit(SCAN_COMPLETED, &local->scanning)) {
                 aborted = test_and_clear_bit(SCAN_ABORTED, &local->scanning);
-                __ieee80211_scan_completed(&local->hw, aborted);
-                return;
-        }
-
-        mutex_lock(&local->mtx);
-        if (!sdata || !local->scan_req) {
-                mutex_unlock(&local->mtx);
-                return;
+                goto out_complete;
         }
 
-        if (local->hw_scan_req) {
-                int rc = drv_hw_scan(local, sdata, local->hw_scan_req);
-                mutex_unlock(&local->mtx);
-                if (rc)
-                        __ieee80211_scan_completed(&local->hw, true);
-                return;
-        }
+        if (!sdata || !local->scan_req)
+                goto out;
 
         if (local->scan_req && !local->scanning) {
                 struct cfg80211_scan_request *req = local->scan_req;
@@ -682,21 +664,21 @@ void ieee80211_scan_work(struct work_struct *work)
                 local->scan_sdata = NULL;
 
                 rc = __ieee80211_start_scan(sdata, req);
-                mutex_unlock(&local->mtx);
-
-                if (rc)
-                        __ieee80211_scan_completed(&local->hw, true);
-                return;
+                if (rc) {
+                        /* need to complete scan in cfg80211 */
+                        local->scan_req = req;
+                        aborted = true;
+                        goto out_complete;
+                } else
+                        goto out;
         }
 
-        mutex_unlock(&local->mtx);
-
         /*
          * Avoid re-scheduling when the sdata is going away.
          */
         if (!ieee80211_sdata_running(sdata)) {
-                __ieee80211_scan_completed(&local->hw, true);
-                return;
+                aborted = true;
+                goto out_complete;
         }
 
         /*
@@ -706,8 +688,12 @@ void ieee80211_scan_work(struct work_struct *work)
         do {
                 switch (local->next_scan_state) {
                 case SCAN_DECISION:
-                        if (ieee80211_scan_state_decision(local, &next_delay))
-                                return;
+                        /* if no more bands/channels left, complete scan */
+                        if (local->scan_channel_idx >= local->scan_req->n_channels) {
+                                aborted = false;
+                                goto out_complete;
+                        }
+                        ieee80211_scan_state_decision(local, &next_delay);
                         break;
                 case SCAN_SET_CHANNEL:
                         ieee80211_scan_state_set_channel(local, &next_delay);
@@ -725,6 +711,19 @@ void ieee80211_scan_work(struct work_struct *work)
         } while (next_delay == 0);
 
         ieee80211_queue_delayed_work(&local->hw, &local->scan_work, next_delay);
+        mutex_unlock(&local->mtx);
+        return;
+
+out_complete:
+        hw_scan = test_bit(SCAN_HW_SCANNING, &local->scanning);
+        finish = __ieee80211_scan_completed(&local->hw, aborted, hw_scan);
+        mutex_unlock(&local->mtx);
+        if (finish)
+                __ieee80211_scan_completed_finish(&local->hw, hw_scan);
+        return;
+
+out:
+        mutex_unlock(&local->mtx);
 }
 
 int ieee80211_request_scan(struct ieee80211_sub_if_data *sdata,
@@ -786,21 +785,40 @@ int ieee80211_request_internal_scan(struct ieee80211_sub_if_data *sdata,
         return ret;
 }
 
+/*
+ * Only call this function when a scan can't be queued -- under RTNL.
+ */
 void ieee80211_scan_cancel(struct ieee80211_local *local)
 {
         bool abortscan;
-
-        cancel_delayed_work_sync(&local->scan_work);
+        bool finish = false;
 
         /*
-         * Only call this function when a scan can't be
-         * queued -- mostly at suspend under RTNL.
+         * We are only canceling software scan, or deferred scan that was not
+         * yet really started (see __ieee80211_start_scan ).
+         *
+         * Regarding hardware scan:
+         * - we can not call  __ieee80211_scan_completed() as when
+         *   SCAN_HW_SCANNING bit is set this function change
+         *   local->hw_scan_req to operate on 5G band, what race with
+         *   driver which can use local->hw_scan_req
+         *
+         * - we can not cancel scan_work since driver can schedule it
+         *   by ieee80211_scan_completed(..., true) to finish scan
+         *
+         * Hence low lever driver is responsible for canceling HW scan.
          */
+
         mutex_lock(&local->mtx);
-        abortscan = test_bit(SCAN_SW_SCANNING, &local->scanning) ||
-                    (!local->scanning && local->scan_req);
+        abortscan = local->scan_req && !test_bit(SCAN_HW_SCANNING, &local->scanning);
+        if (abortscan)
+                finish = __ieee80211_scan_completed(&local->hw, true, false);
         mutex_unlock(&local->mtx);
 
-        if (abortscan)
-                __ieee80211_scan_completed(&local->hw, true);
+        if (abortscan) {
+                /* The scan is canceled, but stop work from being pending */
+                cancel_delayed_work_sync(&local->scan_work);
+        }
+        if (finish)
+                __ieee80211_scan_completed_finish(&local->hw, false);
 }