On Tue, Dec 18, 2018 at 02:17:15PM +0000, Ruhl, Michael J wrote: > >-----Original Message----- > >From: Leon Romanovsky [mailto:leon@xxxxxxxxxx] > >Sent: Tuesday, December 18, 2018 9:00 AM > >To: Ruhl, Michael J <michael.j.ruhl@xxxxxxxxx> > >Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>; Dalessandro, Dennis > ><dennis.dalessandro@xxxxxxxxx>; Yuval Shaia <yuval.shaia@xxxxxxxxxx>; > >Doug Ledford <dledford@xxxxxxxxxx>; Marciniszyn, Mike > ><mike.marciniszyn@xxxxxxxxx>; RDMA mailing list <linux- > >rdma@xxxxxxxxxxxxxxx> > >Subject: Re: [PATCH rdma-next] RDMA/hfi1: Use PCI-ID as an identification in > >debugfs > >> > >> So we get: > >> > >> /sys/kernel/debug/hfi/hfi1_<port> > >> > >> For each HFI we will increment port, so for two instance of the driver, there > >will > >> always be a uniquely defined name. > >> > >> From that perspective, as far as I can tell, the HFI driver is meeting the > >> "globally uniqueness" requirement. > >> > >> We do register with the IB driver using the hfi1_class_name/port, but that is > >a > >> stored separately, and is completely unrelated to our debugfs usage. > >> > >> If the IB name is renamed, there is no effect on the HFI debugfs files. > >> > >> The data structure and function name are perhaps poorly named, but as far > >> as I can tell are unique, and not in conflict with anything from the IB space. > > > >ok, as you wish, let's disable device rename for hfi1. We can't allow > >ambiguity for the users. > > Leon, > > Maybe you need to define "device rename". > > My understanding is that we are talking about the rdma tool function: > > rdma dev rename > > Which is matched with the core function: > > ib_device_rename() > > Is that what you are referring to? Or are you renaming something else? When I'm talking about device rename, I see user space ability from RDMA netlink interface to rename any IB device to any other name, rdmatool is one of the available interfaces, while ib_device_rename() is kernel complimentary part. > > I do not see any relationship to the HFI debugfs directory, or how this is > relates to this function in any way. > > Saying that it is "wrong" and that other drivers do it "differently" is not > explaining why this is not correctly unique, why this will not work if someone > does an ib_device_rename(), or how this is ambiguous. > > What is the ambiguity? > > How is this causing ambiguity for users? > > How does this affect ib_device_rename()? > > Why does this naming convention disrupt the ability of the ib_device_rename() > function to work? My ultimate goal is to combine that RDMA netlink functionality with systemd boot-up scripts. Those scripts are supposed to create unique device names without any relation to the probe order and/or error reset flows. Being part of the boot process, users will see devices in similar to netdevices, e.g. rdma0p3 or xGUID or anything else (less important for now) https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/ From user perspective, administrator will issue "rdma dev"/ibv_devinfo and will see list of already renamed devices. After that the simple lookup in corresponding debugfs entry will show that all devices with correlated names except hfi* are shown there. For hfi1, he will have hard time to translate new name visible in various tools to old name presented in debugfs. This is ambiguity, from my point of view. > > Thanks, > > Mike >
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