cfg80211: refactor cfg80211_bss_update

This patch implements minor refactoring for cfg80211_bss_update function.
Code path for updating known BSS is extracted into dedicated
cfg80211_update_known_bss function.

Signed-off-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>
Link: https://lore.kernel.org/r/20190726163922.27509-2-sergey.matyukevich.os@quantenna.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index a98daba..9119f5c 100644 (file)
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -1091,6 +1091,93 @@ struct cfg80211_non_tx_bss {
        u8 bssid_index;
 };
 
+static bool
+cfg80211_update_known_bss(struct cfg80211_registered_device *rdev,
+                         struct cfg80211_internal_bss *known,
+                         struct cfg80211_internal_bss *new,
+                         bool signal_valid)
+{
+       lockdep_assert_held(&rdev->bss_lock);
+
+       /* Update IEs */
+       if (rcu_access_pointer(new->pub.proberesp_ies)) {
+               const struct cfg80211_bss_ies *old;
+
+               old = rcu_access_pointer(known->pub.proberesp_ies);
+
+               rcu_assign_pointer(known->pub.proberesp_ies,
+                                  new->pub.proberesp_ies);
+               /* Override possible earlier Beacon frame IEs */
+               rcu_assign_pointer(known->pub.ies,
+                                  new->pub.proberesp_ies);
+               if (old)
+                       kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head);
+       } else if (rcu_access_pointer(new->pub.beacon_ies)) {
+               const struct cfg80211_bss_ies *old;
+               struct cfg80211_internal_bss *bss;
+
+               if (known->pub.hidden_beacon_bss &&
+                   !list_empty(&known->hidden_list)) {
+                       const struct cfg80211_bss_ies *f;
+
+                       /* The known BSS struct is one of the probe
+                        * response members of a group, but we're
+                        * receiving a beacon (beacon_ies in the new
+                        * bss is used). This can only mean that the
+                        * AP changed its beacon from not having an
+                        * SSID to showing it, which is confusing so
+                        * drop this information.
+                        */
+
+                       f = rcu_access_pointer(new->pub.beacon_ies);
+                       kfree_rcu((struct cfg80211_bss_ies *)f, rcu_head);
+                       return false;
+               }
+
+               old = rcu_access_pointer(known->pub.beacon_ies);
+
+               rcu_assign_pointer(known->pub.beacon_ies, new->pub.beacon_ies);
+
+               /* Override IEs if they were from a beacon before */
+               if (old == rcu_access_pointer(known->pub.ies))
+                       rcu_assign_pointer(known->pub.ies, new->pub.beacon_ies);
+
+               /* Assign beacon IEs to all sub entries */
+               list_for_each_entry(bss, &known->hidden_list, hidden_list) {
+                       const struct cfg80211_bss_ies *ies;
+
+                       ies = rcu_access_pointer(bss->pub.beacon_ies);
+                       WARN_ON(ies != old);
+
+                       rcu_assign_pointer(bss->pub.beacon_ies,
+                                          new->pub.beacon_ies);
+               }
+
+               if (old)
+                       kfree_rcu((struct cfg80211_bss_ies *)old, rcu_head);
+       }
+
+       known->pub.beacon_interval = new->pub.beacon_interval;
+
+       /* don't update the signal if beacon was heard on
+        * adjacent channel.
+        */
+       if (signal_valid)
+               known->pub.signal = new->pub.signal;
+       known->pub.capability = new->pub.capability;
+       known->ts = new->ts;
+       known->ts_boottime = new->ts_boottime;
+       known->parent_tsf = new->parent_tsf;
+       known->pub.chains = new->pub.chains;
+       memcpy(known->pub.chain_signal, new->pub.chain_signal,
+              IEEE80211_MAX_CHAINS);
+       ether_addr_copy(known->parent_bssid, new->parent_bssid);
+       known->pub.max_bssid_indicator = new->pub.max_bssid_indicator;
+       known->pub.bssid_index = new->pub.bssid_index;
+
+       return true;
+}
+
 /* Returned bss is reference counted and must be cleaned up appropriately. */
 struct cfg80211_internal_bss *
 cfg80211_bss_update(struct cfg80211_registered_device *rdev,
@@ -1114,88 +1201,8 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev,
        found = rb_find_bss(rdev, tmp, BSS_CMP_REGULAR);
 
        if (found) {
-               /* Update IEs */
-               if (rcu_access_pointer(tmp->pub.proberesp_ies)) {
-                       const struct cfg80211_bss_ies *old;
-
-                       old = rcu_access_pointer(found->pub.proberesp_ies);
-
-                       rcu_assign_pointer(found->pub.proberesp_ies,
-                                          tmp->pub.proberesp_ies);
-                       /* Override possible earlier Beacon frame IEs */
-                       rcu_assign_pointer(found->pub.ies,
-                                          tmp->pub.proberesp_ies);
-                       if (old)
-                               kfree_rcu((struct cfg80211_bss_ies *)old,
-                                         rcu_head);
-               } else if (rcu_access_pointer(tmp->pub.beacon_ies)) {
-                       const struct cfg80211_bss_ies *old;
-                       struct cfg80211_internal_bss *bss;
-
-                       if (found->pub.hidden_beacon_bss &&
-                           !list_empty(&found->hidden_list)) {
-                               const struct cfg80211_bss_ies *f;
-
-                               /*
-                                * The found BSS struct is one of the probe
-                                * response members of a group, but we're
-                                * receiving a beacon (beacon_ies in the tmp
-                                * bss is used). This can only mean that the
-                                * AP changed its beacon from not having an
-                                * SSID to showing it, which is confusing so
-                                * drop this information.
-                                */
-
-                               f = rcu_access_pointer(tmp->pub.beacon_ies);
-                               kfree_rcu((struct cfg80211_bss_ies *)f,
-                                         rcu_head);
-                               goto drop;
-                       }
-
-                       old = rcu_access_pointer(found->pub.beacon_ies);
-
-                       rcu_assign_pointer(found->pub.beacon_ies,
-                                          tmp->pub.beacon_ies);
-
-                       /* Override IEs if they were from a beacon before */
-                       if (old == rcu_access_pointer(found->pub.ies))
-                               rcu_assign_pointer(found->pub.ies,
-                                                  tmp->pub.beacon_ies);
-
-                       /* Assign beacon IEs to all sub entries */
-                       list_for_each_entry(bss, &found->hidden_list,
-                                           hidden_list) {
-                               const struct cfg80211_bss_ies *ies;
-
-                               ies = rcu_access_pointer(bss->pub.beacon_ies);
-                               WARN_ON(ies != old);
-
-                               rcu_assign_pointer(bss->pub.beacon_ies,
-                                                  tmp->pub.beacon_ies);
-                       }
-
-                       if (old)
-                               kfree_rcu((struct cfg80211_bss_ies *)old,
-                                         rcu_head);
-               }
-
-               found->pub.beacon_interval = tmp->pub.beacon_interval;
-               /*
-                * don't update the signal if beacon was heard on
-                * adjacent channel.
-                */
-               if (signal_valid)
-                       found->pub.signal = tmp->pub.signal;
-               found->pub.capability = tmp->pub.capability;
-               found->ts = tmp->ts;
-               found->ts_boottime = tmp->ts_boottime;
-               found->parent_tsf = tmp->parent_tsf;
-               found->pub.chains = tmp->pub.chains;
-               memcpy(found->pub.chain_signal, tmp->pub.chain_signal,
-                      IEEE80211_MAX_CHAINS);
-               ether_addr_copy(found->parent_bssid, tmp->parent_bssid);
-               found->pub.max_bssid_indicator = tmp->pub.max_bssid_indicator;
-               found->pub.bssid_index = tmp->pub.bssid_index;
+               if (!cfg80211_update_known_bss(rdev, found, tmp, signal_valid))
+                       goto drop;
        } else {
                struct cfg80211_internal_bss *new;
                struct cfg80211_internal_bss *hidden;