Re: [PATCH 2/2] IB/mad: Use IDR for agent IDs
From: Leon Romanovsky
Date: Wed Jun 13 2018 - 03:37:01 EST
On Tue, Jun 12, 2018 at 05:07:39PM -0700, Matthew Wilcox wrote:
> On Tue, Jun 12, 2018 at 02:33:22PM -0600, Jason Gunthorpe wrote:
> > > @@ -377,13 +378,24 @@ struct ib_mad_agent *ib_register_mad_agent(struct ib_device *device,
> > > goto error4;
> > > }
> > >
> > > - spin_lock_irq(&port_priv->reg_lock);
> > > - mad_agent_priv->agent.hi_tid = atomic_inc_return(&ib_mad_client_id);
> > > + idr_preload(GFP_KERNEL);
> > > + idr_lock(&ib_mad_clients);
> > > + ret2 = idr_alloc_cyclic(&ib_mad_clients, mad_agent_priv, 0,
> > > + (1 << 24), GFP_ATOMIC);
> > I like this series, my only concern is this magic number here, at the
> > very least it deserves a big comment explaining why it
> > exists..
> Yes, you're right. Maybe something like this ...
> * The mlx4 driver uses the top byte to distinguish which virtual function
> * generated the MAD, so we must avoid using it.
> #define AGENT_ID_LIMIT (1 << 24)
> ret2 = idr_alloc_cyclic(&ib_mad_clients, mad_agent_priv, 0,
> AGENT_ID_LIMIT, GFP_ATOMIC);
> > Let me see if I can get someone to give it some test time, I assume
> > you haven't been able to test it it?
> I don't have any IB hardware. Frankly I'm scared of Infiniband ;-)
I took it for regression, reliable results will be after -rc1 only.
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