On Fri, Mar 26, 2021 at 02:36:31PM -0500, Bjorn Helgaas wrote:

On Fri, Mar 26, 2021 at 11:50:44AM -0700, Alexander Duyck wrote:

quoted

I almost wonder if it wouldn't make sense to just partition this up to
handle flexible resources in the future. Maybe something like having
the directory setup such that you have "sriov_resources/msix/" and
then you could have individual files with one for the total and the
rest with the VF BDF naming scheme. Then if we have to, we could add
other subdirectories in the future to handle things like queues in the
future.

Subdirectories would be nice, but Greg KH said earlier in a different
context that there's an issue with them [1].  He went on to say tools
like udev would miss uevents for the subdirs [2].

I don't know whether that's really a problem in this case -- it
doesn't seem like we would care about uevents for files that do MSI-X
vector assignment.

[1] https://lore.kernel.org/linux-pci/20191121211017.GA854512@kroah.com/ (local)
[2] https://lore.kernel.org/linux-pci/20191124170207.GA2267252@kroah.com/ (local)

You can only go "one level deep" on subdirectories tied to a 'struct
device' and have userspace tools know they are still there.  You can do
that by giving an attribute group a "name" for the directory.

Anything more than that just gets very very messy very quickly and I do
not recommend doing that at all.

thanks,

greg k-h