[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>

1 files changed, 18 insertions, 17 deletions

diff --git a/drivers/net/wireless/libertas/scan.c b/drivers/net/wireless/libertas/scan.c
index abc9d563ce46..8aaac5f6c9de 100644
--- 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;