[systemd-devel] udev virtio by-path naming

[Viktor Mihajlovski]

On 01.03.2017 20:23, Viktor Mihajlovski wrote:
> On 01.03.2017 19:44, Daniel P. Berrange wrote:
> [...]
> replying on the list, a bit lengthy
>>
>> Ok, my guest has 4 disks
>>
>>  - sda - virtio-scsi, over virtio-pci transport
>>  - sdb - virtio-scsi, over virtio-mmio transport
>>  - vda - virtio-scsi, over virtio-pci transport
>>  - vdb - virtio-scsi, over virtio-mmio transport
>>
>> with systemd 231 I get these links
>>
>>   platform-3f000000.pcie-pci-0000:00:01.1-virtio-pci-0000:02:00.0-scsi-0:0:0:0 -> ../../sda
>>   platform-3f000000.pcie-pci-0000:00:01.3-virtio-pci-0000:04:00.0 -> ../../vda
> this is somewhat suprising (the pcie-pci-xxxx part), could you once more
> do me a favor and run
>  udevadm info -a /dev/vda
> and paste the output?
nevermind, I think I get it now, the PCI bus is a child to the platform
bus, and the virtio PCI functions are connected via PCI bridges
0000:00:01.1 and 0000:00:01.3
>>   virtio-pci-a003c00.virtio_mmio -> ../../vdb
>>   virtio-pci-a003e00.virtio_mmio-scsi-0:0:0:0 -> ../../sdb
>>
>> after applying your patch I get these links:
>>
>>  platform-3f000000.pcie-pci-0000:00:01.1-virtio-pci-0000:02:00.0-scsi-0:0:0:0 -> ../../sda
>>  platform-3f000000.pcie-pci-0000:00:01.3-virtio-pci-0000:04:00.0 -> ../../vda
> well, these are probably stale links from the old systemd baked into
> your initrd
>>  platform-3f000000.pcie-pci-0000:02:00.0-scsi-0:0:0:0 -> ../../sda
>>  platform-3f000000.pcie-pci-0000:04:00.0 -> ../../vda
> I don't yet understand these, especially why the intermediate pci-xxxx
> id has vanished
that is then correct as well, because the PCI bridges don't contribute
to the path id, which is a bonus effect of removing the special virtio
handling
I think we're good with the patch as is.
[...]
-- 

Mit freundlichen Grüßen/Kind Regards
   Viktor Mihajlovski

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