Re: [dpdk-dev] [PATCH] ethdev: fix data type for port id

[Thomas Monjalon <thomas@monjalon.net>]

27/10/2020 03:46, wangyunjian:
> From: Thomas Monjalon [mailto:thomas@monjalon.net]
> > 26/10/2020 13:33, Andrew Rybchenko:
> > > On 10/26/20 3:29 PM, Thomas Monjalon wrote:
> > > > 26/10/2020 13:24, wangyunjian:
> > > >> From: Yunjian Wang <wangyunjian@huawei.com>
> > > >>
> > > >> The ethdev port id should be 16 bits now. This patch fixes the data
> > > >> type of the variable for 'pid', changing from uint32_t to uint16_t.
> > > >>
> > > >> Fixes: 5b7ba31148a8 ("ethdev: add port ownership")
> > > >
> > > > It was 32-bit on purpose, to avoid overflow in this loop:
> > > > 	for (pid = 0; pid < RTE_MAX_ETHPORTS; pid++)
> > > >
> > > > It is now replaced by RTE_ETH_FOREACH_VALID_DEV, but I wonder
> > > > whether we still have this theoritical overflow risk.
> > > > If yes, we should change more variables to 32-bit.
> > >
> > > Ah, it is too tricky. May be it is better to ensure that
> > > RTE_MAX_ETHPORTS is less or equal to UINT16_MAX?
> > 
> > Yes could be another option.
> > 
> 
> Add a check on RTE_MAX_ETHPORT in rte_eal_init()?

Could be a compilation check done with RTE_BUILD_BUG_ON.