Re: [PATCH rdma-next v2 07/14] RDMA/cma: Be strict with attaching to CMA device

[Leon Romanovsky <leon@kernel.org>]

On Fri, Sep 18, 2020 at 08:26:19PM -0300, Jason Gunthorpe wrote:
> On Mon, Sep 07, 2020 at 03:21:49PM +0300, Leon Romanovsky wrote:
> > From: Leon Romanovsky <leonro@mellanox.com>
> >
> > The RDMA-CM code wasn't consistent in flows that attached to cma_dev,
> > this caused to situations where failure during attach to listen on such
> > device leave RDMA-CM in non-consistent state.
> >
> > Update the listen/attach flow to correctly deal with failures.
> >
> > Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> >  drivers/infiniband/core/cma.c | 197 ++++++++++++++++++++--------------
> >  1 file changed, 114 insertions(+), 83 deletions(-)
> >
> > diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
> > index 3fc3c821743d..ab1f8b707a5b 100644
> > +++ b/drivers/infiniband/core/cma.c
> > @@ -458,8 +458,8 @@ static int cma_igmp_send(struct net_device *ndev, union ib_gid *mgid, bool join)
> >  	return (in_dev) ? 0 : -ENODEV;
> >  }
> >
> > -static void _cma_attach_to_dev(struct rdma_id_private *id_priv,
> > -			       struct cma_device *cma_dev)
> > +static int _cma_attach_to_dev(struct rdma_id_private *id_priv,
> > +			      struct cma_device *cma_dev)
> >  {
> >  	cma_dev_get(cma_dev);
> >  	id_priv->cma_dev = cma_dev;
> > @@ -475,15 +475,22 @@ static void _cma_attach_to_dev(struct rdma_id_private *id_priv,
> >  	rdma_restrack_add(&id_priv->res);
> >
> >  	trace_cm_id_attach(id_priv, cma_dev->device);
> > +	return 0;
> >  }
>
> This commit message doesn't explain this patch at all. This is adding
> a return code to _cma_attach_to_dev because some later patch needs
> it. This should also be ordered directly before the later patch
>
> > -static void cma_listen_on_dev(struct rdma_id_private *id_priv,
> > -			      struct cma_device *cma_dev)
> > +static int cma_listen_on_dev(struct rdma_id_private *id_priv,
> > +			     struct cma_device *cma_dev)
> >  {
> >  	struct rdma_id_private *dev_id_priv;
> >  	struct rdma_cm_id *id;
> > @@ -2491,12 +2500,12 @@ static void cma_listen_on_dev(struct rdma_id_private *id_priv,
> >  	lockdep_assert_held(&lock);
> >
> >  	if (cma_family(id_priv) == AF_IB && !rdma_cap_ib_cm(cma_dev->device, 1))
> > -		return;
> > +		return 0;
> >
> >  	id = __rdma_create_id(net, cma_listen_handler, id_priv, id_priv->id.ps,
> >  			      id_priv->id.qp_type, id_priv->res.kern_name);
> >  	if (IS_ERR(id))
> > -		return;
> > +		return PTR_ERR(id);
>
> And there here it is fixing already missing error handling, seems like
> it could be two patches

I don't think so, it is "visible" only after I changed cma_listen_on_dev() function return type,
which is an outcome of _cma_attach_to_dev() change.

Thanks

>
> Jason