6 files changed, 66 insertions, 24 deletions

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index d95da8f55f6e..aa0e4a12308c 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1005,6 +1005,7 @@ struct cfg80211_ssid {
  * @flags: bit field of flags controlling operation
  * @rates: bitmap of rates to advertise for each band
  * @wiphy: the wiphy this was for
+ * @scan_start: time (in jiffies) when the scan started
  * @wdev: the wireless device to scan for
  * @aborted: (internal) scan request was notified as aborted
  * @no_cck: used to send probe requests at non CCK rate in 2GHz band
@@ -1023,6 +1024,7 @@ struct cfg80211_scan_request {
 
         /* internal */
         struct wiphy *wiphy;
+        unsigned long scan_start;
         bool aborted;
         bool no_cck;
 
@@ -1074,6 +1076,7 @@ struct cfg80211_sched_scan_request {
         /* internal */
         struct wiphy *wiphy;
         struct net_device *dev;
+        unsigned long scan_start;
 
         /* keep last */
         struct ieee80211_channel *channels[0];
diff --git a/include/uapi/linux/nl80211.h b/include/uapi/linux/nl80211.h
index c68e15e41321..0e6277a06c29 100644
--- a/include/uapi/linux/nl80211.h
+++ b/include/uapi/linux/nl80211.h
@@ -3049,6 +3049,7 @@ enum nl80211_ap_sme_features {
  *      equals (SAE) with user space SME (NL80211_CMD_AUTHENTICATE) in station
  *      mode
  * @NL80211_FEATURE_LOW_PRIORITY_SCAN: This driver supports low priority scan
+ * @NL80211_FEATURE_SCAN_FLUSH: Scan flush is supported
  */
 enum nl80211_feature_flags {
         NL80211_FEATURE_SK_TX_STATUS                    = 1 << 0,
@@ -3058,6 +3059,7 @@ enum nl80211_feature_flags {
         NL80211_FEATURE_P2P_DEVICE_NEEDS_CHANNEL        = 1 << 4,
         NL80211_FEATURE_SAE                             = 1 << 5,
         NL80211_FEATURE_LOW_PRIORITY_SCAN               = 1 << 6,
+        NL80211_FEATURE_SCAN_FLUSH                      = 1 << 7,
 };
 
 /**
@@ -3100,9 +3102,11 @@ enum nl80211_connect_failed_reason {
  * requests.
  *
  * @NL80211_SCAN_FLAG_LOW_PRIORITY: scan request has low priority
+ * @NL80211_SCAN_FLAG_FLUSH: flush cache before scanning
  */
 enum nl80211_scan_flags {
         NL80211_SCAN_FLAG_LOW_PRIORITY                  = 1<<0,
+        NL80211_SCAN_FLAG_FLUSH                         = 1<<1,
 };
 
 #endif /* __LINUX_NL80211_H */
diff --git a/net/wireless/core.c b/net/wireless/core.c
index 443d4d7deea2..48c2ea4712e9 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -370,6 +370,8 @@ struct wiphy *wiphy_new(const struct cfg80211_ops *ops, int sizeof_priv)
         rdev->wiphy.rts_threshold = (u32) -1;
         rdev->wiphy.coverage_class = 0;
 
+        rdev->wiphy.features = NL80211_FEATURE_SCAN_FLUSH;
+
         return &rdev->wiphy;
 }
 EXPORT_SYMBOL(wiphy_new);
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index aee252d65b8f..9e5a7206b0b4 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -4371,8 +4371,10 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
         if (info->attrs[NL80211_ATTR_SCAN_FLAGS]) {
                 request->flags = nla_get_u32(
                         info->attrs[NL80211_ATTR_SCAN_FLAGS]);
-                if ((request->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) &&
-                    !(wiphy->features & NL80211_FEATURE_LOW_PRIORITY_SCAN)) {
+                if (((request->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) &&
+                     !(wiphy->features & NL80211_FEATURE_LOW_PRIORITY_SCAN)) ||
+                    ((request->flags & NL80211_SCAN_FLAG_FLUSH) &&
+                     !(wiphy->features & NL80211_FEATURE_SCAN_FLUSH))) {
                         err = -EOPNOTSUPP;
                         goto out_free;
                 }
@@ -4383,6 +4385,7 @@ static int nl80211_trigger_scan(struct sk_buff *skb, struct genl_info *info)
 
         request->wdev = wdev;
         request->wiphy = &rdev->wiphy;
+        request->scan_start = jiffies;
 
         rdev->scan_req = request;
         err = rdev->ops->scan(&rdev->wiphy, request);
@@ -4612,8 +4615,10 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
         if (info->attrs[NL80211_ATTR_SCAN_FLAGS]) {
                 request->flags = nla_get_u32(
                         info->attrs[NL80211_ATTR_SCAN_FLAGS]);
-                if ((request->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) &&
-                    !(wiphy->features & NL80211_FEATURE_LOW_PRIORITY_SCAN)) {
+                if (((request->flags & NL80211_SCAN_FLAG_LOW_PRIORITY) &&
+                     !(wiphy->features & NL80211_FEATURE_LOW_PRIORITY_SCAN)) ||
+                    ((request->flags & NL80211_SCAN_FLAG_FLUSH) &&
+                     !(wiphy->features & NL80211_FEATURE_SCAN_FLUSH))) {
                         err = -EOPNOTSUPP;
                         goto out_free;
                 }
@@ -4622,6 +4627,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
         request->dev = dev;
         request->wiphy = &rdev->wiphy;
         request->interval = interval;
+        request->scan_start = jiffies;
 
         err = rdev->ops->sched_scan_start(&rdev->wiphy, dev, request);
         if (!err) {
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 20050965abca..a8d5a9a07e49 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -47,6 +47,27 @@ static void __cfg80211_unlink_bss(struct cfg80211_registered_device *dev,
         kref_put(&bss->ref, bss_release);
 }
 
+/* must hold dev->bss_lock! */
+static void __cfg80211_bss_expire(struct cfg80211_registered_device *dev,
+                                  unsigned long expire_time)
+{
+        struct cfg80211_internal_bss *bss, *tmp;
+        bool expired = false;
+
+        list_for_each_entry_safe(bss, tmp, &dev->bss_list, list) {
+                if (atomic_read(&bss->hold))
+                        continue;
+                if (!time_after(expire_time, bss->ts))
+                        continue;
+
+                __cfg80211_unlink_bss(dev, bss);
+                expired = true;
+        }
+
+        if (expired)
+                dev->bss_generation++;
+}
+
 void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak)
 {
         struct cfg80211_scan_request *request;
@@ -72,10 +93,17 @@ void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev, bool leak)
         if (wdev->netdev)
                 cfg80211_sme_scan_done(wdev->netdev);
 
-        if (request->aborted)
+        if (request->aborted) {
                 nl80211_send_scan_aborted(rdev, wdev);
-        else
+        } else {
+                if (request->flags & NL80211_SCAN_FLAG_FLUSH) {
+                        /* flush entries from previous scans */
+                        spin_lock_bh(&rdev->bss_lock);
+                        __cfg80211_bss_expire(rdev, request->scan_start);
+                        spin_unlock_bh(&rdev->bss_lock);
+                }
                 nl80211_send_scan_done(rdev, wdev);
+        }
 
 #ifdef CONFIG_CFG80211_WEXT
         if (wdev->netdev && !request->aborted) {
@@ -126,16 +154,27 @@ EXPORT_SYMBOL(cfg80211_scan_done);
 void __cfg80211_sched_scan_results(struct work_struct *wk)
 {
         struct cfg80211_registered_device *rdev;
+        struct cfg80211_sched_scan_request *request;
 
         rdev = container_of(wk, struct cfg80211_registered_device,
                             sched_scan_results_wk);
 
+        request = rdev->sched_scan_req;
+
         mutex_lock(&rdev->sched_scan_mtx);
 
         /* we don't have sched_scan_req anymore if the scan is stopping */
-        if (rdev->sched_scan_req)
-                nl80211_send_sched_scan_results(rdev,
-                                                rdev->sched_scan_req->dev);
+        if (request) {
+                if (request->flags & NL80211_SCAN_FLAG_FLUSH) {
+                        /* flush entries from previous scans */
+                        spin_lock_bh(&rdev->bss_lock);
+                        __cfg80211_bss_expire(rdev, request->scan_start);
+                        spin_unlock_bh(&rdev->bss_lock);
+                        request->scan_start =
+                                jiffies + msecs_to_jiffies(request->interval);
+                }
+                nl80211_send_sched_scan_results(rdev, request->dev);
+        }
 
         mutex_unlock(&rdev->sched_scan_mtx);
 }
@@ -197,23 +236,9 @@ void cfg80211_bss_age(struct cfg80211_registered_device *dev,
         }
 }
 
-/* must hold dev->bss_lock! */
 void cfg80211_bss_expire(struct cfg80211_registered_device *dev)
 {
-        struct cfg80211_internal_bss *bss, *tmp;
-        bool expired = false;
-
-        list_for_each_entry_safe(bss, tmp, &dev->bss_list, list) {
-                if (atomic_read(&bss->hold))
-                        continue;
-                if (!time_after(jiffies, bss->ts + IEEE80211_SCAN_RESULT_EXPIRE))
-                        continue;
-                __cfg80211_unlink_bss(dev, bss);
-                expired = true;
-        }
-
-        if (expired)
-                dev->bss_generation++;
+        __cfg80211_bss_expire(dev, jiffies - IEEE80211_SCAN_RESULT_EXPIRE);
 }
 
 const u8 *cfg80211_find_ie(u8 eid, const u8 *ies, int len)
@@ -962,6 +987,7 @@ int cfg80211_wext_siwscan(struct net_device *dev,
         creq->ssids = (void *)&creq->channels[n_channels];
         creq->n_channels = n_channels;
         creq->n_ssids = 1;
+        creq->scan_start = jiffies;
 
         /* translate "Scan on frequencies" request */
         i = 0;
diff --git a/net/wireless/sme.c b/net/wireless/sme.c
index 055d59643616..07d717eb9e2a 100644
--- a/net/wireless/sme.c
+++ b/net/wireless/sme.c
@@ -138,6 +138,7 @@ static int cfg80211_conn_scan(struct wireless_dev *wdev)
 
         request->wdev = wdev;
         request->wiphy = &rdev->wiphy;
+        request->scan_start = jiffies;
 
         rdev->scan_req = request;