diff mbox series

[net-next] hv_netvsc: fix vf serial matching with pci slot info

Message ID 20181011201434.30737-1-haiyangz@linuxonhyperv.com
State Changes Requested, archived
Delegated to: David Miller
Headers show
Series [net-next] hv_netvsc: fix vf serial matching with pci slot info | expand

Commit Message

Haiyang Zhang Oct. 11, 2018, 8:14 p.m. UTC 
From: Haiyang Zhang <haiyangz@microsoft.com>

The VF device's serial number is saved as a string in PCI slot's
kobj name, not the slot->number. This patch corrects the netvsc
driver, so the VF device can be successfully paired with synthetic
NIC.

Fixes: 00d7ddba1143 ("hv_netvsc: pair VF based on serial number")
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
---
 drivers/net/hyperv/netvsc_drv.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

Comments

Haiyang Zhang Oct. 11, 2018, 10:30 p.m. UTC | #1 
> -----Original Message-----
> From: Haiyang Zhang <haiyangz@linuxonhyperv.com>
> Sent: Thursday, October 11, 2018 4:15 PM
> To: davem@davemloft.net; netdev@vger.kernel.org
> Cc: Haiyang Zhang <haiyangz@microsoft.com>; KY Srinivasan
> <kys@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>;
> olaf@aepfle.de; vkuznets <vkuznets@redhat.com>;
> devel@linuxdriverproject.org; linux-kernel@vger.kernel.org
> Subject: [PATCH net-next] hv_netvsc: fix vf serial matching with pci slot info
> 
> From: Haiyang Zhang <haiyangz@microsoft.com>
> 
> The VF device's serial number is saved as a string in PCI slot's kobj name, not
> the slot->number. This patch corrects the netvsc driver, so the VF device can be
> successfully paired with synthetic NIC.
> 
> Fixes: 00d7ddba1143 ("hv_netvsc: pair VF based on serial number")
> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>

Thanks Stephen for the reminder -- I added the "reported-by" here:

Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Vitaly Kuznetsov Oct. 12, 2018, 6:27 a.m. UTC | #2 
Haiyang Zhang <haiyangz@microsoft.com> writes:

>> -----Original Message-----
>> From: Haiyang Zhang <haiyangz@linuxonhyperv.com>
>> Sent: Thursday, October 11, 2018 4:15 PM
>> To: davem@davemloft.net; netdev@vger.kernel.org
>> Cc: Haiyang Zhang <haiyangz@microsoft.com>; KY Srinivasan
>> <kys@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>;
>> olaf@aepfle.de; vkuznets <vkuznets@redhat.com>;
>> devel@linuxdriverproject.org; linux-kernel@vger.kernel.org
>> Subject: [PATCH net-next] hv_netvsc: fix vf serial matching with pci slot info
>> 
>> From: Haiyang Zhang <haiyangz@microsoft.com>
>> 
>> The VF device's serial number is saved as a string in PCI slot's kobj name, not
>> the slot->number. This patch corrects the netvsc driver, so the VF device can be
>> successfully paired with synthetic NIC.
>> 
>> Fixes: 00d7ddba1143 ("hv_netvsc: pair VF based on serial number")
>> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
>
> Thanks Stephen for the reminder -- I added the "reported-by" here:
>
> Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>

Thanks) 

The difference in the hack I sent to Stephen was that instead of using
kstrtou32() and checking the return value I opted for snprintf() and
doing strncmp().
gregkh@linuxfoundation.org Oct. 12, 2018, 6:36 a.m. UTC | #3 
On Thu, Oct 11, 2018 at 08:14:34PM +0000, Haiyang Zhang wrote:
> From: Haiyang Zhang <haiyangz@microsoft.com>
> 
> The VF device's serial number is saved as a string in PCI slot's
> kobj name, not the slot->number. This patch corrects the netvsc
> driver, so the VF device can be successfully paired with synthetic
> NIC.
> 
> Fixes: 00d7ddba1143 ("hv_netvsc: pair VF based on serial number")
> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> ---
>  drivers/net/hyperv/netvsc_drv.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
> index 9bcaf204a7d4..8121ce34a39f 100644
> --- a/drivers/net/hyperv/netvsc_drv.c
> +++ b/drivers/net/hyperv/netvsc_drv.c
> @@ -2030,14 +2030,15 @@ static void netvsc_vf_setup(struct work_struct *w)
>  	rtnl_unlock();
>  }
>  
> -/* Find netvsc by VMBus serial number.
> - * The PCI hyperv controller records the serial number as the slot.
> +/* Find netvsc by VF serial number.
> + * The PCI hyperv controller records the serial number as the slot kobj name.
>   */
>  static struct net_device *get_netvsc_byslot(const struct net_device *vf_netdev)
>  {
>  	struct device *parent = vf_netdev->dev.parent;
>  	struct net_device_context *ndev_ctx;
>  	struct pci_dev *pdev;
> +	u32 serial;
>  
>  	if (!parent || !dev_is_pci(parent))
>  		return NULL; /* not a PCI device */
> @@ -2048,16 +2049,22 @@ static struct net_device *get_netvsc_byslot(const struct net_device *vf_netdev)
>  		return NULL;
>  	}
>  
> +	if (kstrtou32(pdev->slot->kobj.name, 10, &serial)) {

kobject_name()?

And that feels _very_ fragile to me.  This is now an api that you are
guaranteeing will never change?

Good luck with that!

greg k-h
Haiyang Zhang Oct. 12, 2018, 5:38 p.m. UTC | #4 
> -----Original Message-----
> From: Greg KH <gregkh@linuxfoundation.org>
> Sent: Friday, October 12, 2018 2:36 AM
> To: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: davem@davemloft.net; netdev@vger.kernel.org; olaf@aepfle.de; Stephen
> Hemminger <sthemmin@microsoft.com>; linux-kernel@vger.kernel.org;
> devel@linuxdriverproject.org; vkuznets <vkuznets@redhat.com>
> Subject: Re: [PATCH net-next] hv_netvsc: fix vf serial matching with pci slot info
> 
> On Thu, Oct 11, 2018 at 08:14:34PM +0000, Haiyang Zhang wrote:
> > From: Haiyang Zhang <haiyangz@microsoft.com>
> >
> > The VF device's serial number is saved as a string in PCI slot's kobj
> > name, not the slot->number. This patch corrects the netvsc driver, so
> > the VF device can be successfully paired with synthetic NIC.
> >
> > Fixes: 00d7ddba1143 ("hv_netvsc: pair VF based on serial number")
> > Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> > ---
> >  drivers/net/hyperv/netvsc_drv.c | 15 +++++++++++----
> >  1 file changed, 11 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/net/hyperv/netvsc_drv.c
> > b/drivers/net/hyperv/netvsc_drv.c index 9bcaf204a7d4..8121ce34a39f
> > 100644
> > --- a/drivers/net/hyperv/netvsc_drv.c
> > +++ b/drivers/net/hyperv/netvsc_drv.c
> > @@ -2030,14 +2030,15 @@ static void netvsc_vf_setup(struct work_struct
> *w)
> >  	rtnl_unlock();
> >  }
> >
> > -/* Find netvsc by VMBus serial number.
> > - * The PCI hyperv controller records the serial number as the slot.
> > +/* Find netvsc by VF serial number.
> > + * The PCI hyperv controller records the serial number as the slot kobj name.
> >   */
> >  static struct net_device *get_netvsc_byslot(const struct net_device
> > *vf_netdev)  {
> >  	struct device *parent = vf_netdev->dev.parent;
> >  	struct net_device_context *ndev_ctx;
> >  	struct pci_dev *pdev;
> > +	u32 serial;
> >
> >  	if (!parent || !dev_is_pci(parent))
> >  		return NULL; /* not a PCI device */ @@ -2048,16 +2049,22
> @@ static
> > struct net_device *get_netvsc_byslot(const struct net_device *vf_netdev)
> >  		return NULL;
> >  	}
> >
> > +	if (kstrtou32(pdev->slot->kobj.name, 10, &serial)) {
> 
> kobject_name()?
> 
> And that feels _very_ fragile to me.  This is now an api that you are
> guaranteeing will never change?

Thanks for the suggestion -- I will update it to use kobject_name() to 
access the name.

For stability, the VF NIC's serial numbers are always unique according
to the Hyper-V documents. Other devices may have same numbers,
but they are not handled by netvsc driver.

Thanks,
- Haiyang
diff mbox series

Patch

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 9bcaf204a7d4..8121ce34a39f 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2030,14 +2030,15 @@  static void netvsc_vf_setup(struct work_struct *w)
 	rtnl_unlock();
 }
 
-/* Find netvsc by VMBus serial number.
- * The PCI hyperv controller records the serial number as the slot.
+/* Find netvsc by VF serial number.
+ * The PCI hyperv controller records the serial number as the slot kobj name.
  */
 static struct net_device *get_netvsc_byslot(const struct net_device *vf_netdev)
 {
 	struct device *parent = vf_netdev->dev.parent;
 	struct net_device_context *ndev_ctx;
 	struct pci_dev *pdev;
+	u32 serial;
 
 	if (!parent || !dev_is_pci(parent))
 		return NULL; /* not a PCI device */
@@ -2048,16 +2049,22 @@  static struct net_device *get_netvsc_byslot(const struct net_device *vf_netdev)
 		return NULL;
 	}
 
+	if (kstrtou32(pdev->slot->kobj.name, 10, &serial)) {
+		netdev_notice(vf_netdev, "Invalid vf serial:%s\n",
+			      pdev->slot->kobj.name);
+		return NULL;
+	}
+
 	list_for_each_entry(ndev_ctx, &netvsc_dev_list, list) {
 		if (!ndev_ctx->vf_alloc)
 			continue;
 
-		if (ndev_ctx->vf_serial == pdev->slot->number)
+		if (ndev_ctx->vf_serial == serial)
 			return hv_get_drvdata(ndev_ctx->device_ctx);
 	}
 
 	netdev_notice(vf_netdev,
-		      "no netdev found for slot %u\n", pdev->slot->number);
+		      "no netdev found for vf serial:%u\n", serial);
 	return NULL;
 }