Re: [patch 1/5][RFC] NET: Change pci_enable_device topci_reenable_device to keep device enable balance

[Brandon Philips <bphilips@suse.de>]

On 17:30 Wed 08 Aug 2007, Ramkrishna Vepa wrote:
> Before slot_reset event is called io_error_detected could be called
> (where pci_disable_device() is called), right? 

Oops!  Right, the documentation says .error_detected is _always_ called
before .slot_reset.  So, this patch is not correct.  Please don't merge
this.

>From Documentation/pci-error-recovery.txt:

STEP 1: Notification
--------------------
Platform calls the error_detected() callback on every instance of
every driver affected by the error.
...

If any driver requested a slot reset (by returning PCI_ERS_RESULT_NEED_RESET),
then recovery proceeds to STEP 4 (Slot Reset).

> The pci_reenable_device() will call enable only if the device was
> enabled before and would not be enabled if the device were disabled. Is
> this the intended behavior?

Yes, you are right.  And no it isn't.

Thanks,

	Brandon

> > -----Original Message-----
> > From: netdev-owner@vger.kernel.org
> [mailto:netdev-owner@vger.kernel.org]
> > On Behalf Of Brandon Philips
> > Sent: Thursday, August 02, 2007 3:44 PM
> > To: netdev@vger.kernel.org
> > Cc: teheo@suse.de; Brandon Philips
> > Subject: [patch 1/5][RFC] NET: Change pci_enable_device
> > topci_reenable_device to keep device enable balance
> > 
> > On a slot_reset event pci_disable_device() is never called so calling
> > pci_enable_device() will unbalance the enable count.
> > 
> > Signed-off-by: Brandon Philips <bphilips@suse.de>
> > 
> > ---
> >  drivers/net/e100.c             |    2 +-
> >  drivers/net/e1000/e1000_main.c |    2 +-
> >  drivers/net/ixgb/ixgb_main.c   |    2 +-
> >  drivers/net/s2io.c             |    2 +-
> >  4 files changed, 4 insertions(+), 4 deletions(-)
> > 
> > Index: linux-2.6/drivers/net/e100.c
> > ===================================================================
> > --- linux-2.6.orig/drivers/net/e100.c
> > +++ linux-2.6/drivers/net/e100.c
> > @@ -2828,7 +2828,7 @@ static pci_ers_result_t e100_io_slot_res
> >  	struct net_device *netdev = pci_get_drvdata(pdev);
> >  	struct nic *nic = netdev_priv(netdev);
> > 
> > -	if (pci_enable_device(pdev)) {
> > +	if (pci_reenable_device(pdev)) {
> >  		printk(KERN_ERR "e100: Cannot re-enable PCI device after
> > reset.\n");
> >  		return PCI_ERS_RESULT_DISCONNECT;
> >  	}
> > Index: linux-2.6/drivers/net/e1000/e1000_main.c
> > ===================================================================
> > --- linux-2.6.orig/drivers/net/e1000/e1000_main.c
> > +++ linux-2.6/drivers/net/e1000/e1000_main.c
> > @@ -5270,7 +5270,7 @@ static pci_ers_result_t e1000_io_slot_re
> >  	struct net_device *netdev = pci_get_drvdata(pdev);
> >  	struct e1000_adapter *adapter = netdev->priv;
> > 
> > -	if (pci_enable_device(pdev)) {
> > +	if (pci_reenable_device(pdev)) {
> >  		printk(KERN_ERR "e1000: Cannot re-enable PCI device
> after
> > reset.\n");
> >  		return PCI_ERS_RESULT_DISCONNECT;
> >  	}
> > Index: linux-2.6/drivers/net/ixgb/ixgb_main.c
> > ===================================================================
> > --- linux-2.6.orig/drivers/net/ixgb/ixgb_main.c
> > +++ linux-2.6/drivers/net/ixgb/ixgb_main.c
> > @@ -2294,7 +2294,7 @@ static pci_ers_result_t ixgb_io_slot_res
> >  	struct net_device *netdev = pci_get_drvdata(pdev);
> >  	struct ixgb_adapter *adapter = netdev_priv(netdev);
> > 
> > -	if(pci_enable_device(pdev)) {
> > +	if(pci_reenable_device(pdev)) {
> >  		DPRINTK(PROBE, ERR, "Cannot re-enable PCI device after
> > reset.\n");
> >  		return PCI_ERS_RESULT_DISCONNECT;
> >  	}
> > Index: linux-2.6/drivers/net/s2io.c
> > ===================================================================
> > --- linux-2.6.orig/drivers/net/s2io.c
> > +++ linux-2.6/drivers/net/s2io.c
> > @@ -7833,7 +7833,7 @@ static pci_ers_result_t s2io_io_slot_res
> >  	struct net_device *netdev = pci_get_drvdata(pdev);
> >  	struct s2io_nic *sp = netdev->priv;
> > 
> > -	if (pci_enable_device(pdev)) {
> > +	if (pci_reenable_device(pdev)) {
> >  		printk(KERN_ERR "s2io: "
> >  		       "Cannot re-enable PCI device after reset.\n");
> >  		return PCI_ERS_RESULT_DISCONNECT;
> > 
> > --
> > -
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