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>

1 files changed, 89 insertions, 82 deletions

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index a98dabab557a..9119f5ce3677 100644
--- 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;