RE: [EXTERNAL] Re: [PATCH rdma-next 1/3] RDMA/mana_ib: Access remote atomic for MRs

[Konstantin Taranov]

> On Thu, Apr 10, 2025 at 01:37:00PM +0000, Konstantin Taranov wrote:
> > > > @@ -24,6 +24,9 @@ mana_ib_verbs_to_gdma_access_flags(int
> > > access_flags)
> > > >  	if (access_flags & IB_ACCESS_REMOTE_READ)
> > > >  		flags |= GDMA_ACCESS_FLAG_REMOTE_READ;
> > > >
> > > > +	if (access_flags & IB_ACCESS_REMOTE_ATOMIC)
> > > > +		flags |= GDMA_ACCESS_FLAG_REMOTE_ATOMIC;
> > >
> > > Can you enable this flag unconditionally without relation to running RW?
> >
> > Yes, ATOMIC access does not depend on Remote Read and Remote Write.
> 
> The question is "do you have FW which doesn't support
> GDMA_ACCESS_FLAG_REMOTE_ATOMIC? and what will happen if such flag
> used for such FW?"

As far as I am aware, all FW support this flag.
Nonetheless, if FW does not support it, the HW request to create MR will fail.

> 
> > I also do not see any conditions in other drivers.
> 
> At least for mlx5, we are checking FW capability if it is supported.
> See get_unchangeable_access_flags().
> 
> >
> > - Konstantin
> >
> > >
> > > Thanks
> > >
> > > > +
> > > >  	return flags;
> > > >  }
> > > >
> > > > --
> > > > 2.43.0
> > > >