Patchwork pcnet32: VLB support fixes

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Submitter Bartlomiej Zolnierkiewicz
Date July 30, 2009, 9:17 p.m.
Message ID <200907302317.52648.bzolnier@gmail.com>
Download mbox | patch
Permalink /patch/30398/
State Accepted
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Bartlomiej Zolnierkiewicz - July 30, 2009, 9:17 p.m.
From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Subject: [PATCH] pcnet32: VLB support fixes

VLB support has been broken since at least 2004-2005 period as some
changes introduced back then assumed that ->pci_dev is always valid,
lets try to fix it:

- remove duplicated SET_NETDEV_DEV() call

- call SET_NETDEV_DEV() only for PCI devices

- check for ->pci_dev validity in pcnet32_open()

[ Alternatively we may consider removing VLB support but there would not
  be much gain in it since an extra driver code needed for VLB support is
  minimal and quite simple. ]

This takes care of the following entry from Dan's list:

drivers/net/pcnet32.c +1889 pcnet32_probe1(298) warning: variable derefenced before check 'pdev'

Reported-by: Dan Carpenter <error27@gmail.com>
Cc: corbet@lwn.net
Cc: eteo@redhat.com
Cc: Julia Lawall <julia@diku.dk>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
---
PS I still keep the original cc: list from the smatch thread -- please let
me know if you don't want to be spammed.. ;-)

 drivers/net/pcnet32.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

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Jeff Garzik - July 30, 2009, 9:32 p.m.
Bartlomiej Zolnierkiewicz wrote:
> From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
> Subject: [PATCH] pcnet32: VLB support fixes
> 
> VLB support has been broken since at least 2004-2005 period as some
> changes introduced back then assumed that ->pci_dev is always valid,
> lets try to fix it:
> 
> - remove duplicated SET_NETDEV_DEV() call
> 
> - call SET_NETDEV_DEV() only for PCI devices
> 
> - check for ->pci_dev validity in pcnet32_open()
> 
> [ Alternatively we may consider removing VLB support but there would not
>   be much gain in it since an extra driver code needed for VLB support is
>   minimal and quite simple. ]
> 
> This takes care of the following entry from Dan's list:
> 
> drivers/net/pcnet32.c +1889 pcnet32_probe1(298) warning: variable derefenced before check 'pdev'
> 
> Reported-by: Dan Carpenter <error27@gmail.com>
> Cc: corbet@lwn.net
> Cc: eteo@redhat.com
> Cc: Julia Lawall <julia@diku.dk>
> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
> ---
> PS I still keep the original cc: list from the smatch thread -- please let
> me know if you don't want to be spammed.. ;-)
> 
>  drivers/net/pcnet32.c |   12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)

ACK -- the patch is correct AFAICS -- but would it not be better to have 
a struct device for the VLB device?

We have capability to create struct device for isa and eisa, so VLB is 
quite doable.

	Jeff, who converted old-ISDN ISA+EISA+PCI drivers to
	      hotplug model, once upon a time



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Bartlomiej Zolnierkiewicz - July 30, 2009, 9:46 p.m.
On Thursday 30 July 2009 23:32:19 Jeff Garzik wrote:
> Bartlomiej Zolnierkiewicz wrote:
> > From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
> > Subject: [PATCH] pcnet32: VLB support fixes
> > 
> > VLB support has been broken since at least 2004-2005 period as some
> > changes introduced back then assumed that ->pci_dev is always valid,
> > lets try to fix it:
> > 
> > - remove duplicated SET_NETDEV_DEV() call
> > 
> > - call SET_NETDEV_DEV() only for PCI devices
> > 
> > - check for ->pci_dev validity in pcnet32_open()
> > 
> > [ Alternatively we may consider removing VLB support but there would not
> >   be much gain in it since an extra driver code needed for VLB support is
> >   minimal and quite simple. ]
> > 
> > This takes care of the following entry from Dan's list:
> > 
> > drivers/net/pcnet32.c +1889 pcnet32_probe1(298) warning: variable derefenced before check 'pdev'
> > 
> > Reported-by: Dan Carpenter <error27@gmail.com>
> > Cc: corbet@lwn.net
> > Cc: eteo@redhat.com
> > Cc: Julia Lawall <julia@diku.dk>
> > Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
> > ---
> > PS I still keep the original cc: list from the smatch thread -- please let
> > me know if you don't want to be spammed.. ;-)
> > 
> >  drivers/net/pcnet32.c |   12 +++++++-----
> >  1 file changed, 7 insertions(+), 5 deletions(-)
> 
> ACK -- the patch is correct AFAICS -- but would it not be better to have 
> a struct device for the VLB device?

Sure, such addition would be needed for sysfs support on VLB devices..

> We have capability to create struct device for isa and eisa, so VLB is 
> quite doable.
> 
> 	Jeff, who converted old-ISDN ISA+EISA+PCI drivers to
> 	      hotplug model, once upon a time

..and it seems that you've the needed experience! :)
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Jeff Garzik - July 30, 2009, 9:58 p.m.
Bartlomiej Zolnierkiewicz wrote:
> On Thursday 30 July 2009 23:32:19 Jeff Garzik wrote:
>> Bartlomiej Zolnierkiewicz wrote:
>>> From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
>>> Subject: [PATCH] pcnet32: VLB support fixes
>>>
>>> VLB support has been broken since at least 2004-2005 period as some
>>> changes introduced back then assumed that ->pci_dev is always valid,
>>> lets try to fix it:
>>>
>>> - remove duplicated SET_NETDEV_DEV() call
>>>
>>> - call SET_NETDEV_DEV() only for PCI devices
>>>
>>> - check for ->pci_dev validity in pcnet32_open()
>>>
>>> [ Alternatively we may consider removing VLB support but there would not
>>>   be much gain in it since an extra driver code needed for VLB support is
>>>   minimal and quite simple. ]
>>>
>>> This takes care of the following entry from Dan's list:
>>>
>>> drivers/net/pcnet32.c +1889 pcnet32_probe1(298) warning: variable derefenced before check 'pdev'
>>>
>>> Reported-by: Dan Carpenter <error27@gmail.com>
>>> Cc: corbet@lwn.net
>>> Cc: eteo@redhat.com
>>> Cc: Julia Lawall <julia@diku.dk>
>>> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
>>> ---
>>> PS I still keep the original cc: list from the smatch thread -- please let
>>> me know if you don't want to be spammed.. ;-)
>>>
>>>  drivers/net/pcnet32.c |   12 +++++++-----
>>>  1 file changed, 7 insertions(+), 5 deletions(-)
>> ACK -- the patch is correct AFAICS -- but would it not be better to have 
>> a struct device for the VLB device?
> 
> Sure, such addition would be needed for sysfs support on VLB devices..


>> We have capability to create struct device for isa and eisa, so VLB is 
>> quite doable.
>>
>> 	Jeff, who converted old-ISDN ISA+EISA+PCI drivers to
>> 	      hotplug model, once upon a time
> 
> ..and it seems that you've the needed experience! :)

<grin>  In my esteemed experience, I point you to the 39-line 
include/linux/isa.h as a starting point for grep...  :)

	Jeff




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Bartlomiej Zolnierkiewicz - July 30, 2009, 10:25 p.m.
On Thursday 30 July 2009 23:58:00 Jeff Garzik wrote:
> Bartlomiej Zolnierkiewicz wrote:
> > On Thursday 30 July 2009 23:32:19 Jeff Garzik wrote:
> >> Bartlomiej Zolnierkiewicz wrote:
> >>> From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
> >>> Subject: [PATCH] pcnet32: VLB support fixes
> >>>
> >>> VLB support has been broken since at least 2004-2005 period as some
> >>> changes introduced back then assumed that ->pci_dev is always valid,
> >>> lets try to fix it:
> >>>
> >>> - remove duplicated SET_NETDEV_DEV() call
> >>>
> >>> - call SET_NETDEV_DEV() only for PCI devices
> >>>
> >>> - check for ->pci_dev validity in pcnet32_open()
> >>>
> >>> [ Alternatively we may consider removing VLB support but there would not
> >>>   be much gain in it since an extra driver code needed for VLB support is
> >>>   minimal and quite simple. ]
> >>>
> >>> This takes care of the following entry from Dan's list:
> >>>
> >>> drivers/net/pcnet32.c +1889 pcnet32_probe1(298) warning: variable derefenced before check 'pdev'
> >>>
> >>> Reported-by: Dan Carpenter <error27@gmail.com>
> >>> Cc: corbet@lwn.net
> >>> Cc: eteo@redhat.com
> >>> Cc: Julia Lawall <julia@diku.dk>
> >>> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
> >>> ---
> >>> PS I still keep the original cc: list from the smatch thread -- please let
> >>> me know if you don't want to be spammed.. ;-)
> >>>
> >>>  drivers/net/pcnet32.c |   12 +++++++-----
> >>>  1 file changed, 7 insertions(+), 5 deletions(-)
> >> ACK -- the patch is correct AFAICS -- but would it not be better to have 
> >> a struct device for the VLB device?
> > 
> > Sure, such addition would be needed for sysfs support on VLB devices..
> 
> 
> >> We have capability to create struct device for isa and eisa, so VLB is 
> >> quite doable.
> >>
> >> 	Jeff, who converted old-ISDN ISA+EISA+PCI drivers to
> >> 	      hotplug model, once upon a time
> > 
> > ..and it seems that you've the needed experience! :)
> 
> <grin>  In my esteemed experience, I point you to the 39-line 
> include/linux/isa.h as a starting point for grep...  :)

Send patches.

I don't have a time/motivation for enhancing VLB support, not even
mentioning the access to hardware needed to test such changes..
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David Miller - Aug. 2, 2009, 7:30 p.m.
From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Date: Thu, 30 Jul 2009 23:17:52 +0200

> From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
> Subject: [PATCH] pcnet32: VLB support fixes
> 
> VLB support has been broken since at least 2004-2005 period as some
> changes introduced back then assumed that ->pci_dev is always valid,
> lets try to fix it:
> 
> - remove duplicated SET_NETDEV_DEV() call
> 
> - call SET_NETDEV_DEV() only for PCI devices
> 
> - check for ->pci_dev validity in pcnet32_open()
> 
> [ Alternatively we may consider removing VLB support but there would not
>   be much gain in it since an extra driver code needed for VLB support is
>   minimal and quite simple. ]
> 
> This takes care of the following entry from Dan's list:
> 
> drivers/net/pcnet32.c +1889 pcnet32_probe1(298) warning: variable derefenced before check 'pdev'
> 
> Reported-by: Dan Carpenter <error27@gmail.com>
> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Also applied, thanks.
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Patch

Index: b/drivers/net/pcnet32.c
===================================================================
--- a/drivers/net/pcnet32.c
+++ b/drivers/net/pcnet32.c
@@ -1719,7 +1719,9 @@  pcnet32_probe1(unsigned long ioaddr, int
 		ret = -ENOMEM;
 		goto err_release_region;
 	}
-	SET_NETDEV_DEV(dev, &pdev->dev);
+
+	if (pdev)
+		SET_NETDEV_DEV(dev, &pdev->dev);
 
 	if (pcnet32_debug & NETIF_MSG_PROBE)
 		printk(KERN_INFO PFX "%s at %#3lx,", chipname, ioaddr);
@@ -1818,7 +1820,6 @@  pcnet32_probe1(unsigned long ioaddr, int
 
 	spin_lock_init(&lp->lock);
 
-	SET_NETDEV_DEV(dev, &pdev->dev);
 	lp->name = chipname;
 	lp->shared_irq = shared;
 	lp->tx_ring_size = TX_RING_SIZE;	/* default tx ring size */
@@ -2089,6 +2090,7 @@  static void pcnet32_free_ring(struct net
 static int pcnet32_open(struct net_device *dev)
 {
 	struct pcnet32_private *lp = netdev_priv(dev);
+	struct pci_dev *pdev = lp->pci_dev;
 	unsigned long ioaddr = dev->base_addr;
 	u16 val;
 	int i;
@@ -2149,9 +2151,9 @@  static int pcnet32_open(struct net_devic
 	lp->a.write_csr(ioaddr, 124, val);
 
 	/* Allied Telesyn AT 2700/2701 FX are 100Mbit only and do not negotiate */
-	if (lp->pci_dev->subsystem_vendor == PCI_VENDOR_ID_AT &&
-	    (lp->pci_dev->subsystem_device == PCI_SUBDEVICE_ID_AT_2700FX ||
-	     lp->pci_dev->subsystem_device == PCI_SUBDEVICE_ID_AT_2701FX)) {
+	if (pdev && pdev->subsystem_vendor == PCI_VENDOR_ID_AT &&
+	    (pdev->subsystem_device == PCI_SUBDEVICE_ID_AT_2700FX ||
+	     pdev->subsystem_device == PCI_SUBDEVICE_ID_AT_2701FX)) {
 		if (lp->options & PCNET32_PORT_ASEL) {
 			lp->options = PCNET32_PORT_FD | PCNET32_PORT_100;
 			if (netif_msg_link(lp))