[ofa-general] Re: [PATCH for-2.6.22] IB/cm: improve local id allocation

[Roland Dreier]

 > A quick looks makes it look like idr stuff is *really* not designed to
 > get a negative input: and note that old code has the wrap-around problem, too.
 > So, I think the following would be a better fix:

Yes, that's basically what I just proposed (although see below).  It
all looks pretty safe to me...  Sean, what do you think about this for
2.6.22?

 > diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
 > index eff591d..5e77b01 100644
 > --- a/drivers/infiniband/core/cm.c
 > +++ b/drivers/infiniband/core/cm.c
 > @@ -306,7 +306,9 @@ static int cm_alloc_id(struct cm_id_private *cm_id_priv)
 >  	do {
 >  		spin_lock_irqsave(&cm.lock, flags);
 >  		ret = idr_get_new_above(&cm.local_id_table, cm_id_priv,
 > -					next_id++, &id);
 > +					next_id, &id);
 > +		if (!ret)
 > +			next_id = id == 0x7ffffff ? 0 : id + 1;

...except I used MAX_INT here, and indeed your patch only has 6 'f's
in that constant.  Actually digging a little I see that we should use
MAX_ID_MASK to be really correct.