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

From: Jason Gunthorpe <jgg@nvidia.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: Doug Ledford <dledford@redhat.com>, <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH rdma-next v2 07/14] RDMA/cma: Be strict with attaching to CMA device
Date: Thu, 24 Sep 2020 16:46:19 -0300	[thread overview]
Message-ID: <20200924194619.GO9475@nvidia.com> (raw)
In-Reply-To: <20200919090340.GB869610@unreal>

On Sat, Sep 19, 2020 at 12:03:40PM +0300, Leon Romanovsky wrote:
> 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.

If the first patch adds this missing error handling to
cam_listen_on_dev, then the 2nd patch adds new error handling to
_cma_attach_to_dev() it would be much clearer what this is all about.

Jason

> Thanks
> 
> >
> > Jason