Re: [patch net-next 3/9] mlx4: Implement port type setting via devlink interface

Tue, Feb 23, 2016 at 05:45:07PM CET, hannes@stressinduktion.org wrote:

On 23.02.2016 17:04, Jiri Pirko wrote:

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Tue, Feb 23, 2016 at 04:57:17PM CET, hannes@stressinduktion.org wrote:

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On 23.02.2016 16:30, Jiri Pirko wrote:

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Tue, Feb 23, 2016 at 04:16:11PM CET, hannes@stressinduktion.org wrote:

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1) is easily solvable, just drop the ifindex style attributes and always
force the user to enter the bus and bus-topology id.

But why? Use can easily get that info and map it to devlink index. It
aligns with nl80211 iface.

Do you really want to do commands like:
myhost:~$ dl dev show pci_0000:01:00.0
?

Yes, exactly I would. I would put them into a boot-up script based on my
system configuration and can be sure it will work the next boot, too, and
adapt them when I replace the hardware or do some configuration changes.

I think sysadmins or scripts are the primary users of this interface not
kernel developers which switch their settings around all the time, no?

I can easily add this to the userspace tool to accept "pci_0000:01:00.0"
format and to map it internally to devlink index. No problem.

I argue for this stable topology identifier to be the default. Especially if
you add device info before the actual module is loaded (this is during
initramfs, when udev cannot rename devlink names to stable ones), a user has
to deal with pre-devlink-ids before rename and after. Do you have plans how
to address that?

You can still access devlink using pci_addr using dl. I don't see a
problem.

I don't really see a reason why the devlink indexes/names exist inside the
kernel instead of a stable topology identifier. They confuse users and add
more unnecessary code to the kernel. Shells have environment variables for
that. ;) This is a low-level kernel setting tool IMHO.

I just see the problem that users use the devlink* names and we get reports
because stuff breaks because they don't use the stable identifiers. That is
all.

you can have stable devlink name using udev. For pre-udev usage, you can
use pci address directly. I don't like to use pci address for every
dl command. I would like to have some more convenient name handle -
devlink name.

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Current initramfs for stable interface names uses EUI48 based mac addresses
most of the time and udev runs then after the pivot_root.

The devlink names can easily be aliases in user space.

I don't want to store them anywhere. I just use "dl" tool and pass the
name there.

Sorry?

you said - "The devlink names can easily be aliases in user space." -
where do you want to store them?