diff mbox series

[RFC,3/3] mt76x02: remove bogus mutex usage

Message ID 20190416091305.4218-4-sgruszka@redhat.com (mailing list archive)
State RFC
Delegated to: Felix Fietkau
Headers show
Series mt76: suspend/stop/removal fixes | expand

Commit Message

Stanislaw Gruszka April 16, 2019, 9:13 a.m. UTC 
mac .start(), .stop() callbacks are never called concurrently with other
mac callbacks. The only concurencly is with mt76 works which we cancel
on stop() and schedule on start().

This fixes possible deadlock on cancel_delayed_work_sync(&dev->mac_work)
as mac_work also take mutex.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
---
 .../net/wireless/mediatek/mt76/mt76x0/pci.c   |  6 -----
 .../net/wireless/mediatek/mt76/mt76x0/usb.c   | 22 +++++--------------
 .../wireless/mediatek/mt76/mt76x2/pci_main.c  |  5 -----
 .../wireless/mediatek/mt76/mt76x2/usb_main.c  | 10 ++-------
 4 files changed, 7 insertions(+), 36 deletions(-)

Comments

Lorenzo Bianconi April 16, 2019, 9:29 a.m. UTC | #1 
> mac .start(), .stop() callbacks are never called concurrently with other
> mac callbacks. The only concurencly is with mt76 works which we cancel
> on stop() and schedule on start().
> 
> This fixes possible deadlock on cancel_delayed_work_sync(&dev->mac_work)
> as mac_work also take mutex.
> 
> Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
> ---
>  .../net/wireless/mediatek/mt76/mt76x0/pci.c   |  6 -----
>  .../net/wireless/mediatek/mt76/mt76x0/usb.c   | 22 +++++--------------
>  .../wireless/mediatek/mt76/mt76x2/pci_main.c  |  5 -----
>  .../wireless/mediatek/mt76/mt76x2/usb_main.c  | 10 ++-------
>  4 files changed, 7 insertions(+), 36 deletions(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76x0/pci.c b/drivers/net/wireless/mediatek/mt76/mt76x0/pci.c
> index 156d3d064ba0..ac979128386a 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76x0/pci.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt76x0/pci.c
> @@ -25,8 +25,6 @@ static int mt76x0e_start(struct ieee80211_hw *hw)
>  {
>  	struct mt76x02_dev *dev = hw->priv;
>  
> -	mutex_lock(&dev->mt76.mutex);
> -
>  	mt76x02_mac_start(dev);
>  	mt76x0_phy_calibrate(dev, true);
>  	ieee80211_queue_delayed_work(dev->mt76.hw, &dev->mac_work,
> @@ -35,8 +33,6 @@ static int mt76x0e_start(struct ieee80211_hw *hw)
>  				     MT_CALIBRATE_INTERVAL);
>  	set_bit(MT76_STATE_RUNNING, &dev->mt76.state);
>  
> -	mutex_unlock(&dev->mt76.mutex);
> -
>  	return 0;
>  }
>  
> @@ -62,10 +58,8 @@ static void mt76x0e_stop(struct ieee80211_hw *hw)
>  {
>  	struct mt76x02_dev *dev = hw->priv;
>  
> -	mutex_lock(&dev->mt76.mutex);
>  	clear_bit(MT76_STATE_RUNNING, &dev->mt76.state);
>  	mt76x0e_stop_hw(dev);
> -	mutex_unlock(&dev->mt76.mutex);
>  }
>  
>  static void

[..]

>  static const struct ieee80211_ops mt76x0u_ops = {
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76x2/pci_main.c b/drivers/net/wireless/mediatek/mt76/mt76x2/pci_main.c
> index 16dc8e2451b5..1b5caabebff5 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76x2/pci_main.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt76x2/pci_main.c
> @@ -22,8 +22,6 @@ mt76x2_start(struct ieee80211_hw *hw)
>  	struct mt76x02_dev *dev = hw->priv;
>  	int ret;
>  
> -	mutex_lock(&dev->mt76.mutex);
> -
>  	ret = mt76x2_mac_start(dev);
>  	if (ret)
>  		goto out;

You can remove goto here and just return ret (same below)

> @@ -40,7 +38,6 @@ mt76x2_start(struct ieee80211_hw *hw)
>  	set_bit(MT76_STATE_RUNNING, &dev->mt76.state);
>  
>  out:
> -	mutex_unlock(&dev->mt76.mutex);
>  	return ret;
>  }
>  
> @@ -49,10 +46,8 @@ mt76x2_stop(struct ieee80211_hw *hw)
>  {
>  	struct mt76x02_dev *dev = hw->priv;
>  
> -	mutex_lock(&dev->mt76.mutex);
>  	clear_bit(MT76_STATE_RUNNING, &dev->mt76.state);
>  	mt76x2_stop_hardware(dev);
> -	mutex_unlock(&dev->mt76.mutex);
>  }
>  
>  static int
> diff --git a/drivers/net/wireless/mediatek/mt76/mt76x2/usb_main.c b/drivers/net/wireless/mediatek/mt76/mt76x2/usb_main.c
> index 0771de210c6a..32726b4906ea 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt76x2/usb_main.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt76x2/usb_main.c
> @@ -21,30 +21,24 @@ static int mt76x2u_start(struct ieee80211_hw *hw)
>  	struct mt76x02_dev *dev = hw->priv;
>  	int ret;
>  
> -	mutex_lock(&dev->mt76.mutex);
> -
>  	ret = mt76x2u_mac_start(dev);
>  	if (ret)
> -		goto out;
> +		return ret;
>  
>  	ieee80211_queue_delayed_work(mt76_hw(dev), &dev->mac_work,
>  				     MT_MAC_WORK_INTERVAL);
>  	set_bit(MT76_STATE_RUNNING, &dev->mt76.state);
>  
> -out:
> -	mutex_unlock(&dev->mt76.mutex);
> -	return ret;
> +	return 0;
>  }
>  
>  static void mt76x2u_stop(struct ieee80211_hw *hw)
>  {
>  	struct mt76x02_dev *dev = hw->priv;
>  
> -	mutex_lock(&dev->mt76.mutex);
>  	clear_bit(MT76_STATE_RUNNING, &dev->mt76.state);
>  	mt76u_stop_tx(&dev->mt76);
>  	mt76x2u_stop_hw(dev);
> -	mutex_unlock(&dev->mt76.mutex);
>  }
>  
>  static int
> -- 
> 2.20.1
>
diff mbox series

Patch

diff --git a/drivers/net/wireless/mediatek/mt76/mt76x0/pci.c b/drivers/net/wireless/mediatek/mt76/mt76x0/pci.c
index 156d3d064ba0..ac979128386a 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x0/pci.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x0/pci.c
@@ -25,8 +25,6 @@  static int mt76x0e_start(struct ieee80211_hw *hw)
 {
 	struct mt76x02_dev *dev = hw->priv;
 
-	mutex_lock(&dev->mt76.mutex);
-
 	mt76x02_mac_start(dev);
 	mt76x0_phy_calibrate(dev, true);
 	ieee80211_queue_delayed_work(dev->mt76.hw, &dev->mac_work,
@@ -35,8 +33,6 @@  static int mt76x0e_start(struct ieee80211_hw *hw)
 				     MT_CALIBRATE_INTERVAL);
 	set_bit(MT76_STATE_RUNNING, &dev->mt76.state);
 
-	mutex_unlock(&dev->mt76.mutex);
-
 	return 0;
 }
 
@@ -62,10 +58,8 @@  static void mt76x0e_stop(struct ieee80211_hw *hw)
 {
 	struct mt76x02_dev *dev = hw->priv;
 
-	mutex_lock(&dev->mt76.mutex);
 	clear_bit(MT76_STATE_RUNNING, &dev->mt76.state);
 	mt76x0e_stop_hw(dev);
-	mutex_unlock(&dev->mt76.mutex);
 }
 
 static void
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x0/usb.c b/drivers/net/wireless/mediatek/mt76/mt76x0/usb.c
index 22c10722019d..494b9f35f80d 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x0/usb.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x0/usb.c
@@ -81,8 +81,10 @@  static void mt76x0u_cleanup(struct mt76x02_dev *dev)
 	mt76u_queues_deinit(&dev->mt76);
 }
 
-static void mt76x0u_mac_stop(struct mt76x02_dev *dev)
+static void mt76x0u_stop(struct ieee80211_hw *hw)
 {
+	struct mt76x02_dev *dev = hw->priv;
+
 	clear_bit(MT76_STATE_RUNNING, &dev->mt76.state);
 	cancel_delayed_work_sync(&dev->cal_work);
 	cancel_delayed_work_sync(&dev->mac_work);
@@ -106,11 +108,9 @@  static int mt76x0u_start(struct ieee80211_hw *hw)
 	struct mt76x02_dev *dev = hw->priv;
 	int ret;
 
-	mutex_lock(&dev->mt76.mutex);
-
 	ret = mt76x0_mac_start(dev);
 	if (ret)
-		goto out;
+		return ret;
 
 	mt76x0_phy_calibrate(dev, true);
 	ieee80211_queue_delayed_work(dev->mt76.hw, &dev->mac_work,
@@ -118,19 +118,7 @@  static int mt76x0u_start(struct ieee80211_hw *hw)
 	ieee80211_queue_delayed_work(dev->mt76.hw, &dev->cal_work,
 				     MT_CALIBRATE_INTERVAL);
 	set_bit(MT76_STATE_RUNNING, &dev->mt76.state);
-
-out:
-	mutex_unlock(&dev->mt76.mutex);
-	return ret;
-}
-
-static void mt76x0u_stop(struct ieee80211_hw *hw)
-{
-	struct mt76x02_dev *dev = hw->priv;
-
-	mutex_lock(&dev->mt76.mutex);
-	mt76x0u_mac_stop(dev);
-	mutex_unlock(&dev->mt76.mutex);
+	return 0;
 }
 
 static const struct ieee80211_ops mt76x0u_ops = {
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x2/pci_main.c b/drivers/net/wireless/mediatek/mt76/mt76x2/pci_main.c
index 16dc8e2451b5..1b5caabebff5 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x2/pci_main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x2/pci_main.c
@@ -22,8 +22,6 @@  mt76x2_start(struct ieee80211_hw *hw)
 	struct mt76x02_dev *dev = hw->priv;
 	int ret;
 
-	mutex_lock(&dev->mt76.mutex);
-
 	ret = mt76x2_mac_start(dev);
 	if (ret)
 		goto out;
@@ -40,7 +38,6 @@  mt76x2_start(struct ieee80211_hw *hw)
 	set_bit(MT76_STATE_RUNNING, &dev->mt76.state);
 
 out:
-	mutex_unlock(&dev->mt76.mutex);
 	return ret;
 }
 
@@ -49,10 +46,8 @@  mt76x2_stop(struct ieee80211_hw *hw)
 {
 	struct mt76x02_dev *dev = hw->priv;
 
-	mutex_lock(&dev->mt76.mutex);
 	clear_bit(MT76_STATE_RUNNING, &dev->mt76.state);
 	mt76x2_stop_hardware(dev);
-	mutex_unlock(&dev->mt76.mutex);
 }
 
 static int
diff --git a/drivers/net/wireless/mediatek/mt76/mt76x2/usb_main.c b/drivers/net/wireless/mediatek/mt76/mt76x2/usb_main.c
index 0771de210c6a..32726b4906ea 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76x2/usb_main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76x2/usb_main.c
@@ -21,30 +21,24 @@  static int mt76x2u_start(struct ieee80211_hw *hw)
 	struct mt76x02_dev *dev = hw->priv;
 	int ret;
 
-	mutex_lock(&dev->mt76.mutex);
-
 	ret = mt76x2u_mac_start(dev);
 	if (ret)
-		goto out;
+		return ret;
 
 	ieee80211_queue_delayed_work(mt76_hw(dev), &dev->mac_work,
 				     MT_MAC_WORK_INTERVAL);
 	set_bit(MT76_STATE_RUNNING, &dev->mt76.state);
 
-out:
-	mutex_unlock(&dev->mt76.mutex);
-	return ret;
+	return 0;
 }
 
 static void mt76x2u_stop(struct ieee80211_hw *hw)
 {
 	struct mt76x02_dev *dev = hw->priv;
 
-	mutex_lock(&dev->mt76.mutex);
 	clear_bit(MT76_STATE_RUNNING, &dev->mt76.state);
 	mt76u_stop_tx(&dev->mt76);
 	mt76x2u_stop_hw(dev);
-	mutex_unlock(&dev->mt76.mutex);
 }
 
 static int