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Message-ID: <4C909CAD.8010905@kernel.org>
Date: Wed, 15 Sep 2010 14:15:09 +0400
From: Denis Kirjanov <dkirjanov@...nel.org>
To: netdev@...r.kernel.org
CC: Eric Dumazet <eric.dumazet@...il.com>,
"David S. Miller" <davem@...emloft.net>, ben@...adent.org.uk
Subject: Re: [PATCH] 3c59x: Remove atomic context inside vortex_{set|get}_wol
On 09/15/2010 10:35 AM, Eric Dumazet wrote:
> Le mercredi 15 septembre 2010 à 06:24 +0000, Denis Kirjanov a écrit :
>> There is no need to use spinlocks in vortex_{set|get}_wol.
>> This also fixes a bug:
>> [ 254.214993] 3c59x 0000:00:0d.0: PME# enabled
>> [ 254.215021] BUG: sleeping function called from invalid context at kernel/mutex.c:94
>> [ 254.215030] in_atomic(): 0, irqs_disabled(): 1, pid: 4875, name: ethtool
>> [ 254.215042] Pid: 4875, comm: ethtool Tainted: G W 2.6.36-rc3+ #7
>> [ 254.215049] Call Trace:
>> [ 254.215050] [] __might_sleep+0xb1/0xb6
>> [ 254.215050] [] mutex_lock+0x17/0x30
>> [ 254.215050] [] acpi_enable_wakeup_device_power+0x2b/0xb1
>> [ 254.215050] [] acpi_pm_device_sleep_wake+0x42/0x7f
>> [ 254.215050] [] acpi_pci_sleep_wake+0x5d/0x63
>> [ 254.215050] [] platform_pci_sleep_wake+0x1d/0x20
>> [ 254.215050] [] __pci_enable_wake+0x90/0xd0
>> [ 254.215050] [] acpi_set_WOL+0x8e/0xf5 [3c59x]
>> [ 254.215050] [] vortex_set_wol+0x4e/0x5e [3c59x]
>> [ 254.215050] [] dev_ethtool+0x1cf/0xb61
>> [ 254.215050] [] ? debug_mutex_free_waiter+0x45/0x4a
>> [ 254.215050] [] ? __mutex_lock_common+0x204/0x20e
>> [ 254.215050] [] ? __mutex_lock_slowpath+0x12/0x15
>> [ 254.215050] [] ? mutex_lock+0x23/0x30
>> [ 254.215050] [] dev_ioctl+0x42c/0x533
>> [ 254.215050] [] ? _cond_resched+0x8/0x1c
>> [ 254.215050] [] ? lock_page+0x1c/0x30
>> [ 254.215050] [] ? page_address+0x15/0x7c
>> [ 254.215050] [] ? filemap_fault+0x187/0x2c4
>> [ 254.215050] [] sock_ioctl+0x1d4/0x1e0
>> [ 254.215050] [] ? sock_ioctl+0x0/0x1e0
>> [ 254.215050] [] vfs_ioctl+0x19/0x33
>> [ 254.215050] [] do_vfs_ioctl+0x424/0x46f
>> [ 254.215050] [] ? selinux_file_ioctl+0x3c/0x40
>> [ 254.215050] [] sys_ioctl+0x40/0x5a
>> [ 254.215050] [] sysenter_do_call+0x12/0x22
>>
>> vortex_set_wol protected with a spinlock, but nested acpi_set_WOL acquires a mutex inside atomic context.
>> Ethtool operations are already serialized by RTNL mutex, so it is safe to drop the locks.
>>
>> Signed-off-by: Denis Kirjanov <dkirjanov@...nel.org>
>> ---
>> drivers/net/3c59x.c | 6 ++----
>> 1 files changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/net/3c59x.c b/drivers/net/3c59x.c
>> index 7a01588..a5c697b 100644
>> --- a/drivers/net/3c59x.c
>> +++ b/drivers/net/3c59x.c
>> @@ -634,6 +634,8 @@ struct vortex_private {
>> medialock:1,
>> must_free_region:1, /* Flag: if zero, Cardbus owns the I/O region */
>> large_frames:1; /* accept large frames */
>> + /* {get|set}_wol operations are already serialized by rtnl.
>> + * no additional locking is required for the enable_wol and acpi_set_WOL() */
>
> Please format this comment like this :
>
> /* This is a fine ............................
> * and long comment ..................................
> */
>
>> int drv_flags;
>> u16 status_enable;
>> u16 intr_enable;
>> @@ -2922,13 +2924,11 @@ static void vortex_get_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
>> {
>> struct vortex_private *vp = netdev_priv(dev);
>>
>> - spin_lock_irq(&vp->lock);
>> wol->supported = WAKE_MAGIC;
>>
>> wol->wolopts = 0;
>> if (vp->enable_wol)
>> wol->wolopts |= WAKE_MAGIC;
>> - spin_unlock_irq(&vp->lock);
>> }
>>
>> static int vortex_set_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
>> @@ -2937,13 +2937,11 @@ static int vortex_set_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
>> if (wol->wolopts & ~WAKE_MAGIC)
>> return -EINVAL;
>>
>> - spin_lock_irq(&vp->lock);
>> if (wol->wolopts & WAKE_MAGIC)
>> vp->enable_wol = 1;
>> else
>> vp->enable_wol = 0;
>> acpi_set_WOL(dev);
>> - spin_unlock_irq(&vp->lock);
>>
>> return 0;
>> }
>
>
Comments fixed, thanks Eric
---
drivers/net/3c59x.c | 7 +++----
1 files changed, 3 insertions(+), 4 deletions(-)
diff --git a/drivers/net/3c59x.c b/drivers/net/3c59x.c
index 7a01588..afcad74 100644
--- a/drivers/net/3c59x.c
+++ b/drivers/net/3c59x.c
@@ -634,6 +634,9 @@ struct vortex_private {
medialock:1,
must_free_region:1, /* Flag: if zero, Cardbus owns the I/O region */
large_frames:1; /* accept large frames */
+ /* {get|set}_wol operations are already serialized by rtnl.
+ * no additional locking is required for the enable_wol and acpi_set_WOL()
+ */
int drv_flags;
u16 status_enable;
u16 intr_enable;
@@ -2922,13 +2925,11 @@ static void vortex_get_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
{
struct vortex_private *vp = netdev_priv(dev);
- spin_lock_irq(&vp->lock);
wol->supported = WAKE_MAGIC;
wol->wolopts = 0;
if (vp->enable_wol)
wol->wolopts |= WAKE_MAGIC;
- spin_unlock_irq(&vp->lock);
}
static int vortex_set_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
@@ -2937,13 +2938,11 @@ static int vortex_set_wol(struct net_device *dev, struct ethtool_wolinfo *wol)
if (wol->wolopts & ~WAKE_MAGIC)
return -EINVAL;
- spin_lock_irq(&vp->lock);
if (wol->wolopts & WAKE_MAGIC)
vp->enable_wol = 1;
else
vp->enable_wol = 0;
acpi_set_WOL(dev);
- spin_unlock_irq(&vp->lock);
return 0;
}
--
1.6.4.4
--
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