Re: [PATCHv10 02/12] ib_core: IBoE CMA device binding

[Roland Dreier <rdreier-FYB4Gu1CFyUAvxtiuMwx3w@public.gmane.org>]

 > The point is it cma_acquire_dev() may get called when
 > dev_addr->transport has not yet been set so we can't rely on its value
 > to retrieve the correct GID; for example when it gets called by
 > rdma_bind_addr() it will only set the transport a few lines down the
 > function when calling cma_attach_to_dev(). That's why I may have to
 > look for the GID in the IBoE case.

I see.  We just have the address but the RDMA CM API doesn't give us the
type exactly (we just know the ARPHRD type).

 > I agree that traversing the list twice does not look so good so how
 > about this:

 > static int cma_acquire_dev(struct rdma_id_private *id_priv)
 > {
 > 	struct rdma_dev_addr *dev_addr = &id_priv->id.route.addr.dev_addr;
 > 	struct cma_device *cma_dev;
 > 	union ib_gid gid, iboe_gid;
 > 	int ret = -ENODEV;
 > 
 > 	iboe_addr_get_sgid(dev_addr, &iboe_gid);
 > 	memcpy(&gid, dev_addr->src_dev_addr +
 > 	       rdma_addr_gid_offset(dev_addr), sizeof gid);

I wish there were a cleaner way to write all this...

 > 	list_for_each_entry(cma_dev, &dev_list, list) {
 > 		ret = ib_find_cached_gid(cma_dev->device, &gid,
 > 					 &id_priv->id.port_num, NULL);
 > 		if (!ret)
 > 			break;
 > 		if (dev_addr->dev_type != ARPHRD_INFINIBAND) {
 > 			ret = ib_find_cached_gid(cma_dev->device, &iboe_gid,
 > 						 &id_priv->id.port_num, NULL);
 > 			if (!ret)
 > 				break;
 > 		}

looks better but since we know everything about the device we're
comparing to, can't we do something like:

		if (addr and dev ARPHRD agree)
			if (dev is IBoE)
				ret = ib_find_gid(iboe_gid);
			else
				ret = ib_find_gid(gid);

		if (!ret)
			break;

(by the way, it seems we can use ib_find_gid() here since we are in a
sleepable context -- no need to rely on the cached_gid stuff, which I
would like to phase out someday)

 > 	}
 > 
 > 	if (!ret)
 > 		cma_attach_to_dev(id_priv, cma_dev);
 > 
 > 	return ret;
 > }
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