On Thu, Nov 05, 2015 at 11:41:57AM +0100, Yann Droneaud wrote:
>
> Those checks were written with the assumption the command and flags
> masks could be different between the legacy and the new verb format.
>
> But since it did happen (yet), it's ok to avoid the duplication (I
> would have prefer a separate preliminary patch for this).
OK, will send in a different patch.
>
>
>
> What about IB_USER_VERBS_CMD_THRESHOLD instead of
> IB_USER_VERBS_CMD_OPEN_QP ?
>
I wanted to be more restrictive here. After all there can't be any
more legacy commands.
> > + !(ib_dev->uverbs_ex_cmd_mask & (1ull <<
> > command))) {
> > ret = -ENOSYS;
> > goto out;
> > }
>
>
> uverbs_ex_cmd_table[] has already been looked up at this point, so that
> can only work if uverbs_ex_cmd_table[] is extended to support the
> legacy verbs.
>
> Currently there's only two verbs with dual implementation
>
> IB_USER_VERBS_EX_CMD_QUERY_DEVICE
> IB_USER_VERBS_EX_CMD_CREATE_CQ
>
>
> If we want to have a 1:1 mapping legacy verbs as extended verbs, then I
> would suggest to check the legacy mask to not allow a legacy verb not
> supported by the hw provider to be called:
>
> if (! (((command <= IB_USER_VERBS_CMD_OPEN_QP) ?
> ib_dev->uverbs_cmd_mask :
> ib_dev->uverbs_ex_cmd_mask) & (1 ull << command))) {
> ret = -ENOSYS;
> goto out;
> }
>
Yes this looks even safer. So I will apply this idea and re-send.
> Perhaps we could drop uverbs_ex_cmd_mask and set bit for extended verbs
> in uverbs_cmd_mask instead. Then, there will be no need to check againt
> the command threshold.
>
> Anyway, this is a new assumption that extended verbs will have to be
> somewhat retro compatible with the legacy hw provider implementation
> used by the legacy verbs they intend to replace: an extended verbs
> matching a legacy one will need to be written in such way it will not
> be calling into a hw provider function pointer that can be NULL (in
> case there's new function pointer is added for an updated verbs in
> struct ib_device while we keep in place the legacy one ... but for in
> -kernel drivers that should never happen: it usual better to replace
> the previous one by the newer and the existing drivers have to be
> updated to provide the new function and remove the previous one, so I
> think it's quite safe).
>
> Regards.
>
> --
> Yann Droneaud
> OPTEYA
>
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