Re: rdma-core: pvrdma init issue

[Leon Romanovsky <leonro-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org>]

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And now with correct email address.

On Thu, Jan 19, 2017 at 04:05:36PM +0200, Yishai Hadas wrote:
> Hi Adit,
>
> Working with latest rdma-core stuff that includes the pvrdma provider,
> encountered below issue, would appreciate your input on.
>
> While libibverbs loads the drivers there are few "annoying" warnings that
> are printed from pvrdma per uverbs sysfs entry coming from
> 'pvrdma_driver_init_shared'.
>
> "pvrdma: ABI version 4 of /sys/class/infiniband_verbs/uverbs0 is not
> supported (supported 3)
> pvrdma: ABI version 1 of /sys/class/infiniband_verbs/uverbs1 is not
> supported (supported 3)
> ...
> "
>
> Similar messages basically appear in other drivers after some pre- detection
> that the sysfs entry relates to their driver based on vendor id, device name
> but the ABI is not supported.(see mlx5_driver_init)
>
> In the pvrdma driver you are using the ABI version as the detection and as a
> result print some redundant/annoying messages into stdout when working with
> some other device. (e.g. ibv_rc_pingpong -d mlx5_0).
>
> In addition,
> Can you please explain the detection logic itself ? your code chose the
> value of 3 (i.e. PVRDMA_UVERBS_ABI_VERSION) with some comment as of:
> "We support only a single ABI version for now".
>
> What if some other kernel driver uses that value as well or in the future
> you'll add some value that is already in use ? It might cause that pvrdma
> user driver will be used for that device without a real plan by the
> application.
>
> For example if mlx4_0 will report same ABI version the call will end-up with
> an ib_device having below information:
> "dev_name=uverbs0, drive_name=pvrdma, name=mlx4_0"
>
> Yishai
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