From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Monjalon <thomas@monjalon.net>
Subject: Re: [dpdk-stable] [PATCH 10/11] net/failsafe: fix
	sub-device ownership race
Date: Wed, 09 May 2018 23:59:38 +0200
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Cc: Matan Azrad <matan@mellanox.com>, "dev@dpdk.org" <dev@dpdk.org>
To: =?ISO-8859-1?Q?Ga=EBtan?= Rivet <gaetan.rivet@6wind.com>
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09/05/2018 16:03, Ga=EBtan Rivet:
> On Wed, May 09, 2018 at 03:43:31PM +0200, Thomas Monjalon wrote:
> > 09/05/2018 15:30, Ga=EBtan Rivet:
> > > On Wed, May 09, 2018 at 01:01:58PM +0000, Matan Azrad wrote:
> > > > Regarding uint32
> > > > The maximum port id number can be 0xffff.
> > > > In this case the loop will be infinite if we use uint16 to iterate =
over all the ports.
> > >=20
> > > If RTE_MAX_ETHPORTS is set to 0xffff, an array rte_eth_devices[0xffff]
> > > would be defined statically, and I think other issues would arise
> > > before our being stuck in an infinite loop?
> > >=20
> > > In any case, if this had to be fixed, then there should be a
> > > BUILD_BUG_ON RTE_MAX_ETHPORTS being 0xffff, in the relevant part of
> > > librte_ethdev, instead of relying on librte_ethdev users skirting
> > > shortfalls of the library. Anyone iterating on port IDs should expect=
 the
> > > port_id type to be sufficient to hold this information.
> >=20
> > Interesting thought.
> > I vote for keeping Matan's option as it is correct,
> > and will accept a patch in 18.08 for your option (BUILD_BUG_ON).
> > Maybe we should send a deprecation notice before limiting the max
> > number of ports to 0xfffe? Or is it ridiculous for such unlikely constr=
aint?
> >=20
> >=20
>=20
> No actually the issue is when RTE_MAX_ETHPORTS is equal (or superior) to
> 0x10000.
>=20
> If this is an issue that you think is worth having a workaround here,
> you should also consider that rte_eth_find_next_owned_by (and
> rte_eth_find_next, even if this one should be phased out), would also
> result in an overflow and an infinite loop.

You get a point. I will remove the workaround uint32_t in v2,
so all the related issues can be fixed at once in a separate patch
using BUILD_BUG_ON.