mwifiex: fix system hang issue in cmd timeout error case

commit b1a47aa5 upstream.

Reported by Tim Shepard:
I was seeing sporadic failures (wedgeups), and the majority of those
failures I saw printed the printouts in mwifiex_cmd_timeout_func with
cmd = 0xe5 which is CMD_802_11_HS_CFG_ENH.  When this happens, two
minutes later I get notified that the rtcwake thread is blocked, like
this:
      INFO: task rtcwake:3495 blocked for more than 120 seconds.

To get the hung thread unblocked we wake up the cmd wait queue and
cancel the ioctl.
Reported-by: Tim Shepard <shep@laptop.org>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/net/wireless/mwifiex/cmdevt.c

@@ -816,9 +816,6 @@ mwifiex_cmd_timeout_func(unsigned long function_context)
 		return;
 	}
 	cmd_node = adapter->curr_cmd;
-	if (cmd_node->wait_q_enabled)
-		adapter->cmd_wait_q.status = -ETIMEDOUT;
-
 	if (cmd_node) {
 		adapter->dbg.timeout_cmd_id =
 			adapter->dbg.last_cmd_id[adapter->dbg.last_cmd_index];
@@ -863,6 +860,14 @@ mwifiex_cmd_timeout_func(unsigned long function_context)
 
 		dev_err(adapter->dev, "ps_mode=%d ps_state=%d\n",
 				adapter->ps_mode, adapter->ps_state);
+
+		if (cmd_node->wait_q_enabled) {
+			adapter->cmd_wait_q.status = -ETIMEDOUT;
+			wake_up_interruptible(&adapter->cmd_wait_q.wait);
+			mwifiex_cancel_pending_ioctl(adapter);
+			/* reset cmd_sent flag to unblock new commands */
+			adapter->cmd_sent = false;
+		}
 	}
 	if (adapter->hw_status == MWIFIEX_HW_STATUS_INITIALIZING)
 		mwifiex_init_fw_complete(adapter);