PCI: hv: Use device serial number as PCI domain

BugLink: http://bugs.launchpad.net/bugs/1667527
Use the device serial number as the PCI domain.  The serial numbers start
with 1 and are unique within a VM.  So names, such as VF NIC names, that
include domain number as part of the name, can be shorter than that based
on part of bus UUID previously.  The new names will also stay same for VMs
created with copied VHD and same number of devices.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
(cherry picked from commit 4a9b0933bdfcd85da840284bf5a0eb17b654b9c2)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c
index cd114c6787be82effd6397534ce35132fee04bf7..ada98569b78ed65561d5fb4479f1eeee62cd00c3 100644 (file)
--- a/drivers/pci/host/pci-hyperv.c
+++ b/drivers/pci/host/pci-hyperv.c
@@ -1317,6 +1317,18 @@ static struct hv_pci_dev *new_pcichild_device(struct hv_pcibus_device *hbus,
        get_pcichild(hpdev, hv_pcidev_ref_initial);
        get_pcichild(hpdev, hv_pcidev_ref_childlist);
        spin_lock_irqsave(&hbus->device_list_lock, flags);
+
+       /*
+        * When a device is being added to the bus, we set the PCI domain
+        * number to be the device serial number, which is non-zero and
+        * unique on the same VM.  The serial numbers start with 1, and
+        * increase by 1 for each device.  So device names including this
+        * can have shorter names than based on the bus instance UUID.
+        * Only the first device serial number is used for domain, so the
+        * domain number will not change after the first device is added.
+        */
+       if (list_empty(&hbus->children))
+               hbus->sysdata.domain = desc->ser;
        list_add_tail(&hpdev->list_entry, &hbus->children);
        spin_unlock_irqrestore(&hbus->device_list_lock, flags);
        return hpdev;