Re: [PATCH 06/20] RDMA/mlx5: Implement mlx5_ib_map_mr_sg_pi and mlx5_ib_alloc_mr_integrity

[Max Gurtovoy <maxg@xxxxxxxxxxxx>]

On 6/4/2019 10:38 AM, Christoph Hellwig wrote:
> >   int mlx5_ib_dereg_mr(struct ib_mr *ibmr, struct ib_udata *udata)
> >   {
> > -	dereg_mr(to_mdev(ibmr->device), to_mmr(ibmr));
> > +	struct mlx5_ib_mr *mmr = to_mmr(ibmr);
> > +
> > +	if (ibmr->type == IB_MR_TYPE_INTEGRITY)
> > +		dereg_mr(to_mdev(mmr->pi_mr->ibmr.device), mmr->pi_mr);
> > +
> > +	dereg_mr(to_mdev(ibmr->device), mmr);
> Just curious: how could the device for the PI MR be different?  In other
> words, why can't this just be:

The device is not different but we need to do both dereg_mr(mdev, 
mmr->pi_mr) and dereg_mr(mdev, mmr).

> 	struct mlx5_ib_mr *mmr = to_mmr(ibmr);
>
> 	if (ibmr->type == IB_MR_TYPE_INTEGRITY)
> 		mmr = mmr->pi_mr;
> 	dereg_mr(to_mdev(ibmr->device), mmr);