Re: [2.6.37-rc1, patch] gianfar: fix sleep in atomic...

Re: [2.6.37-rc1, patch] gianfar: fix sleep in atomic...

[Rafael J. Wysocki]

On Tuesday, November 02, 2010, Daniel J Blueman wrote:
> Since device_set_wakeup_enable now sleeps, it should not be called
> from a critical section. Since wol_en is not updated elsewhere, we can
> omit the locking entirely.
> 
> Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>

Acked-by: Rafael J. Wysocki <rjw@sisk.pl>

> diff --git a/drivers/net/gianfar_ethtool.c b/drivers/net/gianfar_ethtool.c
> index 5c566eb..e641d7c 100644
> --- a/drivers/net/gianfar_ethtool.c
> +++ b/drivers/net/gianfar_ethtool.c
> @@ -635,10 +635,8 @@ static int gfar_set_wol(struct net_device *dev,
> struct ethtool_wolinfo *wol)
>  	if (wol->wolopts & ~WAKE_MAGIC)
>  		return -EINVAL;
> 
> -	spin_lock_irqsave(&priv->bflock, flags);
>  	priv->wol_en = wol->wolopts & WAKE_MAGIC ? 1 : 0;
>  	device_set_wakeup_enable(&dev->dev, priv->wol_en);
> -	spin_unlock_irqrestore(&priv->bflock, flags);
> 
>  	return 0;
>  }
> 

[PATCH] gianfar: Do not call device_set_wakeup_enable() under a spinlock

[Rafael J. Wysocki]

On Tuesday, November 09, 2010, Rafael J. Wysocki wrote:
> On Tuesday, November 02, 2010, Daniel J Blueman wrote:
> > Since device_set_wakeup_enable now sleeps, it should not be called
> > from a critical section. Since wol_en is not updated elsewhere, we can
> > omit the locking entirely.
> > 
> > Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
> 
> Acked-by: Rafael J. Wysocki <rjw@sisk.pl>

Having reconsidered that I think it may be better to do something like in the
patch below.

This is a regression fix, so please apply if there are no objections.

Thanks,
Rafael

---
From: Rafael J. Wysocki <rjw@sisk.pl>
Subject: gianfar: Do not call device_set_wakeup_enable() under a spinlock

The gianfar driver calls device_set_wakeup_enable() under a spinlock,
which causes a problem to happen after the recent core power
management changes, because this function can sleep now.  Fix this
by moving the device_set_wakeup_enable() call out of the
spinlock-protected area.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 drivers/net/gianfar_ethtool.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Index: linux-2.6/drivers/net/gianfar_ethtool.c
===================================================================
--- linux-2.6.orig/drivers/net/gianfar_ethtool.c
+++ linux-2.6/drivers/net/gianfar_ethtool.c
@@ -635,9 +635,10 @@ static int gfar_set_wol(struct net_devic
 	if (wol->wolopts & ~WAKE_MAGIC)
 		return -EINVAL;
 
+	device_set_wakeup_enable(&dev->dev, wol->wolopts & WAKE_MAGIC);
+
 	spin_lock_irqsave(&priv->bflock, flags);
-	priv->wol_en = wol->wolopts & WAKE_MAGIC ? 1 : 0;
-	device_set_wakeup_enable(&dev->dev, priv->wol_en);
+	priv->wol_en =  !!device_may_wakeup(&dev->dev);
 	spin_unlock_irqrestore(&priv->bflock, flags);
 
 	return 0;

Re: [PATCH] gianfar: Do not call device_set_wakeup_enable() under a spinlock

[David Miller]

From: "Rafael J. Wysocki" <rjw@sisk.pl>
Date: Tue, 9 Nov 2010 22:54:19 +0100

> The gianfar driver calls device_set_wakeup_enable() under a spinlock,
> which causes a problem to happen after the recent core power
> management changes, because this function can sleep now.  Fix this
> by moving the device_set_wakeup_enable() call out of the
> spinlock-protected area.
> 
> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

Patch applied, thank you.