[PATCH] libertas: fix deadlock SIOCGIWSCAN handler

Update signal quality before the locked scan result translation loop,
because calling libertas_prepare_and_send_command() with the
'waitforrsp' option grabs adapter->lock in the command return processing,
leading to the deadlock.

Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/libertas/scan.c b/drivers/net/wireless/libertas/scan.c
index abc9d563ce46fb0e8a633201395cb48c1481580b..8aaac5f6c9dec47739be8ac385424933db72a27c 100644 (file)
--- a/drivers/net/wireless/libertas/scan.c
+++ b/drivers/net/wireless/libertas/scan.c
@@ -1506,7 +1506,6 @@ static inline char *libertas_translate_scan(wlan_private *priv,
        char *current_val;      /* For rates */
        struct iw_event iwe;    /* Temporary buffer */
        int j;
-       int ret;
 #define PERFECT_RSSI ((u8)50)
 #define WORST_RSSI   ((u8)0)
 #define RSSI_DIFF    ((u8)(PERFECT_RSSI - WORST_RSSI))
@@ -1560,22 +1559,18 @@ static inline char *libertas_translate_scan(wlan_private *priv,
                iwe.u.qual.noise =
                    CAL_NF(adapter->NF[TYPE_BEACON][TYPE_NOAVG]);
        }
-       if ((adapter->mode == IW_MODE_AUTO) &&
-           !libertas_SSID_cmp(&adapter->curbssparams.ssid, &bss->ssid)
-           && adapter->adhoccreate) {
-               ret = libertas_prepare_and_send_command(priv,
-                                           cmd_802_11_rssi,
-                                           0,
-                                           cmd_option_waitforrsp,
-                                           0, NULL);
-
-               if (!ret) {
-                       iwe.u.qual.level =
-                           CAL_RSSI(adapter->SNR[TYPE_RXPD][TYPE_AVG] /
-                                    AVG_SCALE,
-                                    adapter->NF[TYPE_RXPD][TYPE_AVG] /
-                                    AVG_SCALE);
-               }
+
+       /* Locally created ad-hoc BSSs won't have beacons if this is the
+        * only station in the adhoc network; so get signal strength
+        * from receive statistics.
+        */
+       if ((adapter->mode == IW_MODE_ADHOC)
+           && adapter->adhoccreate
+           && !libertas_SSID_cmp(&adapter->curbssparams.ssid, &bss->ssid)) {
+               int snr, nf;
+               snr = adapter->SNR[TYPE_RXPD][TYPE_AVG] / AVG_SCALE;
+               nf = adapter->NF[TYPE_RXPD][TYPE_AVG] / AVG_SCALE;
+               iwe.u.qual.level = CAL_RSSI(snr, nf);
        }
        start = iwe_stream_add_event(start, stop, &iwe, IW_EV_QUAL_LEN);
 
@@ -1665,6 +1660,12 @@ int libertas_get_scan(struct net_device *dev, struct iw_request_info *info,
        if (!adapter->nr_cmd_pending && adapter->last_scanned_channel)
                wlan_scan_networks(priv, NULL, 0);
 
+       /* Update RSSI if current BSS is a locally created ad-hoc BSS */
+       if ((adapter->inframode == wlan802_11ibss) && adapter->adhoccreate) {
+               libertas_prepare_and_send_command(priv, cmd_802_11_rssi, 0,
+                                       cmd_option_waitforrsp, 0, NULL);
+       }
+
        mutex_lock(&adapter->lock);
        list_for_each_entry_safe (iter_bss, safe, &adapter->network_list, list) {
                char * next_ev;