Re: [PATCH] RDMA/rxe,siw: Restore uverbs_cmd_mask IB_USER_VERBS_CMD_POST_SEND

[Jason Gunthorpe <jgg@nvidia.com>]

On Fri, Oct 30, 2020 at 11:18:15AM -0500, Bob Pearson wrote:

> This the right short term fix but seriously why not just completely
> kill off uverbs_cmd_mask? If a driver sets a non-NULL value in
> ib_device_ops assume it was done for a reason and allow commands
> through. Is there any example of a driver using uverbs_cmd_mask to
> dynamically enable/disable a verb? I thought this was your plan when
> you mentioned this change a while back.

The remaining ops are all shared with the kernel, so nearly all
drivers set the post_send op but only a few are prepared for it to be
called from userspace.

It is an unfortuante side effect of co-mingling the kernel and user API.

The only way out would be to split the remaining ops into user/kernel
versions and require drivers to set the user op pointer.

These would be effected:

        rdi->ibdev.uverbs_cmd_mask |=
                (1ull << IB_USER_VERBS_CMD_POLL_CQ)             |
                (1ull << IB_USER_VERBS_CMD_REQ_NOTIFY_CQ)       |
                (1ull << IB_USER_VERBS_CMD_POST_SEND)           |
                (1ull << IB_USER_VERBS_CMD_POST_RECV)           |
                (1ull << IB_USER_VERBS_CMD_POST_SRQ_RECV);

I thought about doing it, maybe I should check again

Jason