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

From: Leon Romanovsky <[email-masked]>
Date: Thu, 10 Apr 2025 16:54:34 +0300

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?"

> 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