cfg80211: hold BSS over association process

This fixes the potential issue that the BSS struct that we use
and later assign to wdev->current_bss is removed from the scan
list while associating.

Also warn when we don't have a BSS struct in connect_result
unless it's from a driver that only has the connect() API.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/net/wireless/sme.c b/net/wireless/sme.c
index ae7e2cb..c0bf781 100644
--- a/net/wireless/sme.c
+++ b/net/wireless/sme.c
@@ -615,19 +615,24 @@
 		kfree(wdev->connect_keys);
 		wdev->connect_keys = NULL;
 		wdev->ssid_len = 0;
-		cfg80211_put_bss(wdev->wiphy, bss);
+		if (bss) {
+			cfg80211_unhold_bss(bss_from_pub(bss));
+			cfg80211_put_bss(wdev->wiphy, bss);
+		}
 		return;
 	}
 
-	if (!bss)
+	if (!bss) {
+		WARN_ON_ONCE(!wiphy_to_dev(wdev->wiphy)->ops->connect);
 		bss = cfg80211_get_bss(wdev->wiphy, NULL, bssid,
 				       wdev->ssid, wdev->ssid_len,
 				       WLAN_CAPABILITY_ESS,
 				       WLAN_CAPABILITY_ESS);
-	if (WARN_ON(!bss))
-		return;
+		if (WARN_ON(!bss))
+			return;
+		cfg80211_hold_bss(bss_from_pub(bss));
+	}
 
-	cfg80211_hold_bss(bss_from_pub(bss));
 	wdev->current_bss = bss_from_pub(bss);
 
 	cfg80211_upload_connect_keys(wdev);