wl12xx: avoid blocking while holding rcu lock on bss info change

Some blocking functions were called while holding the rcu lock for
accessing STA information. This can lead to a deadlock.

Save the required info beforehand and release the rcu without
blocking.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

diff --git a/drivers/net/wireless/wl12xx/main.c b/drivers/net/wireless/wl12xx/main.c
index cf8b3ce..d51d559 100644 (file)
--- a/drivers/net/wireless/wl12xx/main.c
+++ b/drivers/net/wireless/wl12xx/main.c
@@ -2222,6 +2222,8 @@ static void wl1271_bss_info_changed_sta(struct wl1271 *wl,
        u32 sta_rate_set = 0;
        int ret;
        struct ieee80211_sta *sta;
+       bool sta_exists = false;
+       struct ieee80211_sta_ht_cap sta_ht_cap;
 
        if (is_ibss) {
                ret = wl1271_bss_beacon_info_changed(wl, vif, bss_conf,
@@ -2293,16 +2295,20 @@ static void wl1271_bss_info_changed_sta(struct wl1271 *wl,
                if (sta->ht_cap.ht_supported)
                        sta_rate_set |=
                            (sta->ht_cap.mcs.rx_mask[0] << HW_HT_RATES_OFFSET);
+               sta_ht_cap = sta->ht_cap;
+               sta_exists = true;
+       }
+       rcu_read_unlock();
 
+       if (sta_exists) {
                /* handle new association with HT and HT information change */
                if ((changed & BSS_CHANGED_HT) &&
                    (bss_conf->channel_type != NL80211_CHAN_NO_HT)) {
-                       ret = wl1271_acx_set_ht_capabilities(wl, &sta->ht_cap,
+                       ret = wl1271_acx_set_ht_capabilities(wl, &sta_ht_cap,
                                                             true);
                        if (ret < 0) {
                                wl1271_warning("Set ht cap true failed %d",
                                               ret);
-                               rcu_read_unlock();
                                goto out;
                        }
                        ret = wl1271_acx_set_ht_information(wl,
@@ -2310,23 +2316,20 @@ static void wl1271_bss_info_changed_sta(struct wl1271 *wl,
                        if (ret < 0) {
                                wl1271_warning("Set ht information failed %d",
                                               ret);
-                               rcu_read_unlock();
                                goto out;
                        }
                }
                /* handle new association without HT and disassociation */
                else if (changed & BSS_CHANGED_ASSOC) {
-                       ret = wl1271_acx_set_ht_capabilities(wl, &sta->ht_cap,
+                       ret = wl1271_acx_set_ht_capabilities(wl, &sta_ht_cap,
                                                             false);
                        if (ret < 0) {
                                wl1271_warning("Set ht cap false failed %d",
                                               ret);
-                               rcu_read_unlock();
                                goto out;
                        }
                }
        }
-       rcu_read_unlock();
 
        if ((changed & BSS_CHANGED_ASSOC)) {
                if (bss_conf->assoc) {