Re: [PATCH v3] net/ixgbe: add proper memory barriers for some Rx functions

[Thomas Monjalon <thomas@monjalon.net>]

13/06/2023 11:25, Ruifeng Wang:
> From: Thomas Monjalon <thomas@monjalon.net>
> > 12/06/2023 13:58, zhoumin:
> > > On Mon, June 12, 2023 at 6:26PM, Thomas Monjalon wrote:
> > > > 15/05/2023 04:10, Zhang, Qi Z:
> > > >> From: Ruifeng Wang <Ruifeng.Wang@arm.com>
> > > >>> From: Min Zhou <zhoumin@loongson.cn>
> > > >>>> ---
> > > >>>> v3:
> > > >>>> - Use rte_smp_rmb() as the proper memory barrier instead of
> > > >>>> rte_rmb()
> > > >>>> ---
> > > >>>> v2:
> > > >>>> - Make the calling of rte_rmb() for all platforms
> > > >>>> ---
> > > > [...]
> > > >>> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > > >> Applied to dpdk-next-net-intel.
> > > >>
> > > >> Thanks
> > > >> Qi
> > > >>
> > > > Why ignoring checkpatch?
> > > > It is saying:
> > > > "
> > > > Warning in drivers/net/ixgbe/ixgbe_rxtx.c:
> > > > Using rte_smp_[r/w]mb
> > > > "
> > >
> > >
> > > I'm sorry. Should we never use rte_smp_[r/w]mb in the driver's code?
> > 
> > No we should avoid.
> > It has been decided to slowly replace such barriers.
> > By the way, I think it is not enough documented.
> > You can find an explanation in doc/guides/rel_notes/deprecation.rst
> > 
> > I think we should also add some notes to lib/eal/include/generic/rte_atomic.h
> > Tyler, Honnappa, Ruifeng, Konstantin, what do you think?
> > 
> 
> Agree that we should add notes to rte_atomic.h.
> The notes were not there for the sake of avoiding warnings on existing occurrences. 
> With Tyler's rte_atomic series merged, rte_atomicNN_xx can be marked as __rte_deprecated.
> rte_smp_*mb can be marked as __rte_deprecated after existing occurrences are converted.

Would you like to add some function comments to explain why it is deprecated?