Re: [PATCH v1 2/5] IB/uverbs: ex_query_device: check request's comp_mask

[Yann Droneaud <ydroneaud-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org>]

Hi,

Le jeudi 29 janvier 2015 à 11:36 -0700, Jason Gunthorpe a écrit :
> On Thu, Jan 29, 2015 at 06:59:59PM +0100, Yann Droneaud wrote:
> > This patch ensures the extended QUERY_DEVICE uverbs request's
> > comp_mask has only known and supported bits (currently none).
> 
> I think I would be happy to see the input comp_mask removed
> entirely. I can't see a possible use for input data to a QUERY command
> that wouldn't be better served by creating a new command
> 
> But forcing the value to 0 seems reasonable as well.
> 

I cannot forsee the future, but having at least one unused bit
available allow for any kind of yet unknown extension: having this
bit/these bits checked now, permit fixing mistake later.

So let it be.

> Reviewed-By: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
> 

Thanks.

> Also, the _ex varients were supposed to be supersets of the base call,
> so it is wrong that query_device_ex doesn't return all the same data
> as query_device, layed out so that the original response structure is
> a prefix of the extended response structure.
> 
> The other _ex calls in verbs were designed that way so it will be
> surprising to the user that this one is different.
> 

It seems to me it has the layout you're expecting:

    224 struct ib_uverbs_ex_query_device_resp {
    225         struct ib_uverbs_query_device_resp base;
    226         __u32 comp_mask;
    227         __u32 reserved;
    228         struct ib_uverbs_odp_caps odp_caps;
    229 };

Regards.

-- 
Yann Droneaud
OPTEYA


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