iwlwifi: do not perferm force reset while doing scan

When uCode error condition detected, driver try to perform either
rf reset or firmware reload in order bring device back to
working condition.

If rf reset is required and scan is in process, there is no need
to issue rf reset since scan already reset the rf.

If firmware reload is required and scan is in process, skip the
reload request. There is a possibility firmware reload during
scan cause problem.

[  485.804046] WARNING: at net/mac80211/main.c:310 ieee80211_restart_hw+0x28/0x62()
[  485.804049] Hardware name: Latitude E6400
[  485.804052] ieee80211_restart_hw called with hardware scan in progress
[  485.804054] Modules linked in: iwlagn iwlcore bnep sco rfcomm l2cap crc16 bluetooth [last unloaded: iwlcore]
[  485.804069] Pid: 812, comm: kworker/u:3 Tainted: G        W   2.6.36-rc3-wl+ #74
[  485.804072] Call Trace:
[  485.804079]  [<c103019a>] warn_slowpath_common+0x60/0x75
[  485.804084]  [<c1030213>] warn_slowpath_fmt+0x26/0x2a
[  485.804089]  [<c145da67>] ieee80211_restart_hw+0x28/0x62
[  485.804102]  [<f8b35dc6>] iwl_bg_restart+0x113/0x150 [iwlagn]
[  485.804108]  [<c10415d5>] process_one_work+0x181/0x25c
[  485.804119]  [<f8b35cb3>] ? iwl_bg_restart+0x0/0x150 [iwlagn]
[  485.804124]  [<c104190a>] worker_thread+0xf9/0x1f2
[  485.804128]  [<c1041811>] ? worker_thread+0x0/0x1f2
[  485.804133]  [<c10451b0>] kthread+0x64/0x69
[  485.804137]  [<c104514c>] ? kthread+0x0/0x69
[  485.804141]  [<c1002df6>] kernel_thread_helper+0x6/0x10
[  485.804145] ---[ end trace 3d4ebdc02d524bbb ]---
[  485.804148] WG> 1
[  485.804153] Pid: 812, comm: kworker/u:3 Tainted: G        W   2.6.36-rc3-wl+ #74
[  485.804156] Call Trace:
[  485.804161]  [<c145da9b>] ? ieee80211_restart_hw+0x5c/0x62
[  485.804172]  [<f8b35dcb>] iwl_bg_restart+0x118/0x150 [iwlagn]
[  485.804177]  [<c10415d5>] process_one_work+0x181/0x25c
[  485.804188]  [<f8b35cb3>] ? iwl_bg_restart+0x0/0x150 [iwlagn]
[  485.804192]  [<c104190a>] worker_thread+0xf9/0x1f2
[  485.804197]  [<c1041811>] ? worker_thread+0x0/0x1f2
[  485.804201]  [<c10451b0>] kthread+0x64/0x69
[  485.804205]  [<c104514c>] ? kthread+0x0/0x69
[  485.804209]  [<c1002df6>] kernel_thread_helper+0x6/0x10

Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com>

drivers/net/wireless/iwlwifi/iwl-core.c

@@ -2613,6 +2613,11 @@ int iwl_force_reset(struct iwl_priv *priv, int mode, bool external)
 	if (test_bit(STATUS_EXIT_PENDING, &priv->status))
 		return -EINVAL;
 
+	if (test_bit(STATUS_SCANNING, &priv->status)) {
+		IWL_DEBUG_INFO(priv, "scan in progress.\n");
+		return -EINVAL;
+	}
+
 	if (mode >= IWL_MAX_FORCE_RESET) {
 		IWL_DEBUG_INFO(priv, "invalid reset request.\n");
 		return -EINVAL;