rtlwifi: Fix kernel Oops "Fw download fail!!"

When connecting to AP, mac80211 asks driver to enter and leave PS quickly,
but driver deinit doesn't wait for delayed work complete when entering PS,
then driver reinit procedure and delay work are running simultaneously.
This will cause unpredictable kernel oops or crash like

rtl8723be: error H2C cmd because of Fw download fail!!!
WARNING: CPU: 3 PID: 159 at drivers/net/wireless/realtek/rtlwifi/
	 rtl8723be/fw.c:227 rtl8723be_fill_h2c_cmd+0x182/0x510 [rtl8723be]
CPU: 3 PID: 159 Comm: kworker/3:2 Tainted: G       O     4.16.13-2-ARCH #1
Hardware name: ASUSTeK COMPUTER INC. X556UF/X556UF, BIOS X556UF.406
	       10/21/2016
Workqueue: rtl8723be_pci rtl_c2hcmd_wq_callback [rtlwifi]
RIP: 0010:rtl8723be_fill_h2c_cmd+0x182/0x510 [rtl8723be]
RSP: 0018:ffffa6ab01e1bd70 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffffa26069071520 RCX: 0000000000000001
RDX: 0000000080000001 RSI: ffffffff8be70e9c RDI: 00000000ffffffff
RBP: 0000000000000000 R08: 0000000000000048 R09: 0000000000000348
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
R13: ffffa26069071520 R14: 0000000000000000 R15: ffffa2607d205f70
FS:  0000000000000000(0000) GS:ffffa26081d80000(0000) knlGS:000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000443b39d3000 CR3: 000000037700a005 CR4: 00000000003606e0
Call Trace:
 ? halbtc_send_bt_mp_operation.constprop.17+0xd5/0xe0 [btcoexist]
 ? ex_btc8723b1ant_bt_info_notify+0x3b8/0x820 [btcoexist]
 ? rtl_c2hcmd_launcher+0xab/0x110 [rtlwifi]
 ? process_one_work+0x1d1/0x3b0
 ? worker_thread+0x2b/0x3d0
 ? process_one_work+0x3b0/0x3b0
 ? kthread+0x112/0x130
 ? kthread_create_on_node+0x60/0x60
 ? ret_from_fork+0x35/0x40
Code: 00 76 b4 e9 e2 fe ff ff 4c 89 ee 4c 89 e7 e8 56 22 86 ca e9 5e ...

This patch ensures all delayed works done before entering PS to satisfy
our expectation, so use cancel_delayed_work_sync() instead. An exception
is delayed work ips_nic_off_wq because running task may be itself, so add
a parameter ips_wq to deinit function to handle this case.

This issue is reported and fixed in below threads:
https://github.com/lwfinger/rtlwifi_new/issues/367
https://github.com/lwfinger/rtlwifi_new/issues/366

Tested-by: Evgeny Kapun <[email protected]> # 8723DE
Tested-by: Shivam Kakkar <[email protected]> # 8723BE on 4.18-rc1
Signed-off-by: Ping-Ke Shih <[email protected]>
Fixes: cceb0a5 ("rtlwifi: Add work queue for c2h cmd.")
Cc: Stable <[email protected]> # 4.11+
Reviewed-by: Larry Finger <[email protected]>
Signed-off-by: Kalle Valo <[email protected]>

Author: Ping-Ke Shih

drivers/net/wireless/realtek/rtlwifi/base.c

@@ -484,18 +484,21 @@ static void _rtl_init_deferred_work(struct ieee80211_hw *hw)
 
 }
 
-void rtl_deinit_deferred_work(struct ieee80211_hw *hw)
+void rtl_deinit_deferred_work(struct ieee80211_hw *hw, bool ips_wq)
 {
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 
 	del_timer_sync(&rtlpriv->works.watchdog_timer);
 
-	cancel_delayed_work(&rtlpriv->works.watchdog_wq);
-	cancel_delayed_work(&rtlpriv->works.ips_nic_off_wq);
-	cancel_delayed_work(&rtlpriv->works.ps_work);
-	cancel_delayed_work(&rtlpriv->works.ps_rfon_wq);
-	cancel_delayed_work(&rtlpriv->works.fwevt_wq);
-	cancel_delayed_work(&rtlpriv->works.c2hcmd_wq);
+	cancel_delayed_work_sync(&rtlpriv->works.watchdog_wq);
+	if (ips_wq)
+		cancel_delayed_work(&rtlpriv->works.ips_nic_off_wq);
+	else
+		cancel_delayed_work_sync(&rtlpriv->works.ips_nic_off_wq);
+	cancel_delayed_work_sync(&rtlpriv->works.ps_work);
+	cancel_delayed_work_sync(&rtlpriv->works.ps_rfon_wq);
+	cancel_delayed_work_sync(&rtlpriv->works.fwevt_wq);
+	cancel_delayed_work_sync(&rtlpriv->works.c2hcmd_wq);
 }
 EXPORT_SYMBOL_GPL(rtl_deinit_deferred_work);
 

drivers/net/wireless/realtek/rtlwifi/base.h

@@ -121,7 +121,7 @@ void rtl_init_rfkill(struct ieee80211_hw *hw);
 void rtl_deinit_rfkill(struct ieee80211_hw *hw);
 
 void rtl_watch_dog_timer_callback(struct timer_list *t);
-void rtl_deinit_deferred_work(struct ieee80211_hw *hw);
+void rtl_deinit_deferred_work(struct ieee80211_hw *hw, bool ips_wq);
 
 bool rtl_action_proc(struct ieee80211_hw *hw, struct sk_buff *skb, u8 is_tx);
 int rtlwifi_rate_mapping(struct ieee80211_hw *hw, bool isht,

drivers/net/wireless/realtek/rtlwifi/core.c

@@ -196,7 +196,7 @@ static void rtl_op_stop(struct ieee80211_hw *hw)
 		/* reset sec info */
 		rtl_cam_reset_sec_info(hw);
 
-		rtl_deinit_deferred_work(hw);
+		rtl_deinit_deferred_work(hw, false);
 	}
 	rtlpriv->intf_ops->adapter_stop(hw);
 

drivers/net/wireless/realtek/rtlwifi/pci.c

@@ -2377,7 +2377,7 @@ void rtl_pci_disconnect(struct pci_dev *pdev)
 		ieee80211_unregister_hw(hw);
 		rtlmac->mac80211_registered = 0;
 	} else {
-		rtl_deinit_deferred_work(hw);
+		rtl_deinit_deferred_work(hw, false);
 		rtlpriv->intf_ops->adapter_stop(hw);
 	}
 	rtlpriv->cfg->ops->disable_interrupt(hw);

drivers/net/wireless/realtek/rtlwifi/ps.c

@@ -71,7 +71,7 @@ bool rtl_ps_disable_nic(struct ieee80211_hw *hw)
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 
 	/*<1> Stop all timer */
-	rtl_deinit_deferred_work(hw);
+	rtl_deinit_deferred_work(hw, true);
 
 	/*<2> Disable Interrupt */
 	rtlpriv->cfg->ops->disable_interrupt(hw);
@@ -292,7 +292,7 @@ void rtl_ips_nic_on(struct ieee80211_hw *hw)
 	struct rtl_ps_ctl *ppsc = rtl_psc(rtl_priv(hw));
 	enum rf_pwrstate rtstate;
 
-	cancel_delayed_work(&rtlpriv->works.ips_nic_off_wq);
+	cancel_delayed_work_sync(&rtlpriv->works.ips_nic_off_wq);
 
 	mutex_lock(&rtlpriv->locks.ips_mutex);
 	if (ppsc->inactiveps) {

drivers/net/wireless/realtek/rtlwifi/usb.c

@@ -1132,7 +1132,7 @@ void rtl_usb_disconnect(struct usb_interface *intf)
 		ieee80211_unregister_hw(hw);
 		rtlmac->mac80211_registered = 0;
 	} else {
-		rtl_deinit_deferred_work(hw);
+		rtl_deinit_deferred_work(hw, false);
 		rtlpriv->intf_ops->adapter_stop(hw);
 	}
 	/*deinit rfkill */