[PATCH 4.9 58/59] rtlwifi: Fix enter/exit power_save

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Larry Finger <Larry.Finger@lwfinger.net>

commit ba9f93f82abafe2552eac942ebb11c2df4f8dd7f upstream.

In commit a5ffbe0a1993 ("rtlwifi: Fix scheduling while atomic bug") and
commit a269913c52ad ("rtlwifi: Rework rtl_lps_leave() and rtl_lps_enter()
to use work queue"), an error was introduced in the power-save routines
due to the fact that leaving PS was delayed by the use of a work queue.

This problem is fixed by detecting if the enter or leave routines are
in interrupt mode. If so, the workqueue is used to place the request.
If in normal mode, the enter or leave routines are called directly.

Fixes: a269913c52ad ("rtlwifi: Rework rtl_lps_leave() and rtl_lps_enter() to use work queue")
Reported-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Stable <stable@vger.kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/wireless/realtek/rtlwifi/base.c |    8 +++---
 drivers/net/wireless/realtek/rtlwifi/core.c |    9 ++-----
 drivers/net/wireless/realtek/rtlwifi/pci.c  |   14 +++-------
 drivers/net/wireless/realtek/rtlwifi/ps.c   |   36 +++++++++++++++++++++-------
 4 files changed, 40 insertions(+), 27 deletions(-)

--- a/drivers/net/wireless/realtek/rtlwifi/base.c
+++ b/drivers/net/wireless/realtek/rtlwifi/base.c
@@ -1303,12 +1303,13 @@ EXPORT_SYMBOL_GPL(rtl_action_proc);
 
 static void setup_arp_tx(struct rtl_priv *rtlpriv, struct rtl_ps_ctl *ppsc)
 {
+	struct ieee80211_hw *hw = rtlpriv->hw;
+
 	rtlpriv->ra.is_special_data = true;
 	if (rtlpriv->cfg->ops->get_btc_status())
 		rtlpriv->btcoexist.btc_ops->btc_special_packet_notify(
 					rtlpriv, 1);
-	rtlpriv->enter_ps = false;
-	schedule_work(&rtlpriv->works.lps_change_work);
+	rtl_lps_leave(hw);
 	ppsc->last_delaylps_stamp_jiffies = jiffies;
 }
 
@@ -1381,8 +1382,7 @@ u8 rtl_is_special_data(struct ieee80211_
 
 		if (is_tx) {
 			rtlpriv->ra.is_special_data = true;
-			rtlpriv->enter_ps = false;
-			schedule_work(&rtlpriv->works.lps_change_work);
+			rtl_lps_leave(hw);
 			ppsc->last_delaylps_stamp_jiffies = jiffies;
 		}
 
--- a/drivers/net/wireless/realtek/rtlwifi/core.c
+++ b/drivers/net/wireless/realtek/rtlwifi/core.c
@@ -1150,10 +1150,8 @@ static void rtl_op_bss_info_changed(stru
 		} else {
 			mstatus = RT_MEDIA_DISCONNECT;
 
-			if (mac->link_state == MAC80211_LINKED) {
-				rtlpriv->enter_ps = false;
-				schedule_work(&rtlpriv->works.lps_change_work);
-			}
+			if (mac->link_state == MAC80211_LINKED)
+				rtl_lps_leave(hw);
 			if (ppsc->p2p_ps_info.p2p_ps_mode > P2P_PS_NONE)
 				rtl_p2p_ps_cmd(hw, P2P_PS_DISABLE);
 			mac->link_state = MAC80211_NOLINK;
@@ -1431,8 +1429,7 @@ static void rtl_op_sw_scan_start(struct
 	}
 
 	if (mac->link_state == MAC80211_LINKED) {
-		rtlpriv->enter_ps = false;
-		schedule_work(&rtlpriv->works.lps_change_work);
+		rtl_lps_leave(hw);
 		mac->link_state = MAC80211_LINKED_SCANNING;
 	} else {
 		rtl_ips_nic_on(hw);
--- a/drivers/net/wireless/realtek/rtlwifi/pci.c
+++ b/drivers/net/wireless/realtek/rtlwifi/pci.c
@@ -663,11 +663,9 @@ tx_status_ok:
 	}
 
 	if (((rtlpriv->link_info.num_rx_inperiod +
-		rtlpriv->link_info.num_tx_inperiod) > 8) ||
-		(rtlpriv->link_info.num_rx_inperiod > 2)) {
-		rtlpriv->enter_ps = false;
-		schedule_work(&rtlpriv->works.lps_change_work);
-	}
+	      rtlpriv->link_info.num_tx_inperiod) > 8) ||
+	      (rtlpriv->link_info.num_rx_inperiod > 2))
+		rtl_lps_leave(hw);
 }
 
 static int _rtl_pci_init_one_rxdesc(struct ieee80211_hw *hw,
@@ -918,10 +916,8 @@ new_trx_end:
 		}
 		if (((rtlpriv->link_info.num_rx_inperiod +
 		      rtlpriv->link_info.num_tx_inperiod) > 8) ||
-		      (rtlpriv->link_info.num_rx_inperiod > 2)) {
-			rtlpriv->enter_ps = false;
-			schedule_work(&rtlpriv->works.lps_change_work);
-		}
+		      (rtlpriv->link_info.num_rx_inperiod > 2))
+			rtl_lps_leave(hw);
 		skb = new_skb;
 no_new:
 		if (rtlpriv->use_new_trx_flow) {
--- a/drivers/net/wireless/realtek/rtlwifi/ps.c
+++ b/drivers/net/wireless/realtek/rtlwifi/ps.c
@@ -407,8 +407,8 @@ void rtl_lps_set_psmode(struct ieee80211
 	}
 }
 
-/*Enter the leisure power save mode.*/
-void rtl_lps_enter(struct ieee80211_hw *hw)
+/* Interrupt safe routine to enter the leisure power save mode.*/
+static void rtl_lps_enter_core(struct ieee80211_hw *hw)
 {
 	struct rtl_mac *mac = rtl_mac(rtl_priv(hw));
 	struct rtl_ps_ctl *ppsc = rtl_psc(rtl_priv(hw));
@@ -444,10 +444,9 @@ void rtl_lps_enter(struct ieee80211_hw *
 
 	spin_unlock_irqrestore(&rtlpriv->locks.lps_lock, flag);
 }
-EXPORT_SYMBOL(rtl_lps_enter);
 
-/*Leave the leisure power save mode.*/
-void rtl_lps_leave(struct ieee80211_hw *hw)
+/* Interrupt safe routine to leave the leisure power save mode.*/
+static void rtl_lps_leave_core(struct ieee80211_hw *hw)
 {
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 	struct rtl_ps_ctl *ppsc = rtl_psc(rtl_priv(hw));
@@ -477,7 +476,6 @@ void rtl_lps_leave(struct ieee80211_hw *
 	}
 	spin_unlock_irqrestore(&rtlpriv->locks.lps_lock, flag);
 }
-EXPORT_SYMBOL(rtl_lps_leave);
 
 /* For sw LPS*/
 void rtl_swlps_beacon(struct ieee80211_hw *hw, void *data, unsigned int len)
@@ -670,12 +668,34 @@ void rtl_lps_change_work_callback(struct
 	struct rtl_priv *rtlpriv = rtl_priv(hw);
 
 	if (rtlpriv->enter_ps)
-		rtl_lps_enter(hw);
+		rtl_lps_enter_core(hw);
 	else
-		rtl_lps_leave(hw);
+		rtl_lps_leave_core(hw);
 }
 EXPORT_SYMBOL_GPL(rtl_lps_change_work_callback);
 
+void rtl_lps_enter(struct ieee80211_hw *hw)
+{
+	struct rtl_priv *rtlpriv = rtl_priv(hw);
+
+	if (!in_interrupt())
+		return rtl_lps_enter_core(hw);
+	rtlpriv->enter_ps = true;
+	schedule_work(&rtlpriv->works.lps_change_work);
+}
+EXPORT_SYMBOL_GPL(rtl_lps_enter);
+
+void rtl_lps_leave(struct ieee80211_hw *hw)
+{
+	struct rtl_priv *rtlpriv = rtl_priv(hw);
+
+	if (!in_interrupt())
+		return rtl_lps_leave_core(hw);
+	rtlpriv->enter_ps = false;
+	schedule_work(&rtlpriv->works.lps_change_work);
+}
+EXPORT_SYMBOL_GPL(rtl_lps_leave);
+
 void rtl_swlps_wq_callback(void *data)
 {
 	struct rtl_works *rtlworks = container_of_dwork_rtl(data,