Re: [PATCH v2 rdma-rc] RDMA/restrack: don't use uaccess_kernel()

[Jason Gunthorpe <jgg-uk2M96/98Pc@public.gmane.org>]

On Wed, Feb 14, 2018 at 06:43:36PM -0800, Steve Wise wrote:
> uaccess_kernel() isn't sufficient to determine if an rdma resource is
> user-mode or not.  For example, resources allocated in the add_one()
> function of an ib_client get falsely labeled as user mode, when they
> are kernel mode allocations.  EG: mad qps.
> 
> The result is that these qps are skipped over during a nldev query
> because of an erroneous namespace mismatch.
> 
> So now we determine if the resource is user-mode by looking at the object
> struct's uobject or similar pointer to know if it was allocated for user
> mode applications.
> 
> Fixes: 02d8883f520e ("RDMA/restrack: Add general infrastructure to track RDMA resources")
> Signed-off-by: Steve Wise <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>
> 
> 
> Changes since v1:
> 
> changed _create_qp() to take the qp ib_uobject ptr so it is availble to
> rdma_restrack_add()
> 
>  drivers/infiniband/core/core_priv.h  |  4 +++-
>  drivers/infiniband/core/restrack.c   | 35 +++++++++++++++++++++++++++++++++--
>  drivers/infiniband/core/uverbs_cmd.c |  4 ++--
>  drivers/infiniband/core/verbs.c      |  3 +--
>  4 files changed, 39 insertions(+), 7 deletions(-)

I took this to for-rc, but when I fixed the XRCD conflict with Leon's
patch I ended up retyping it to this - don't really need all rambly
boilerplate. Someone should fix the other one too..

static bool res_is_user(struct rdma_restrack_entry *res)
{
	switch (res->type) {
	case RDMA_RESTRACK_PD:
		return container_of(res, struct ib_pd, res)->uobject;
	case RDMA_RESTRACK_CQ:
		return container_of(res, struct ib_cq, res)->uobject;
	case RDMA_RESTRACK_QP:
		return container_of(res, struct ib_qp, res)->uobject;
	default:
		WARN_ONCE(true, "Wrong resource tracking type %u\n", res->type);
		return false;
	}
}

Jason
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