Thread (5 messages) flat view 5 messages, 4 authors, 2018-10-12

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

From: Haiyang Zhang <haiyangz@microsoft.com>
Date: 2018-10-12 17:38:46
Also in: lkml

quoted hunk ↗ jump to hunk
-----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 [off-list ref]; linux-kernel@vger.kernel.org;
devel@linuxdriverproject.org; vkuznets [off-list ref]
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:
quoted
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)
quoted
 	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
quoted
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
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