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Commit 80e78ef7 authored by Dan Williams's avatar Dan Williams Committed by John W. Linville
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[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: default avatarDan Williams <dcbw@redhat.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 94b23855

drivers/net/wireless/libertas/scan.c

+18 −17
Original line number Diff line number Diff line
@@ -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;