Re: [PATCH v1] RDMA/sw/rdmavt/mr: Convert to use ERR_CAST()

[Leon Romanovsky]

On Wed, Aug 28, 2024 at 12:06:17PM -0400, Dennis Dalessandro wrote:
> On 8/28/24 4:27 AM, Shen Lichuan wrote:
> > As opposed to open-code, using the ERR_CAST macro clearly indicates that 
> > this is a pointer to an error value and a type conversion was performed.
> > 
> > Signed-off-by: Shen Lichuan <shenlichuan@xxxxxxxx>
> > ---
> >  drivers/infiniband/sw/rdmavt/mr.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/infiniband/sw/rdmavt/mr.c b/drivers/infiniband/sw/rdmavt/mr.c
> > index 7a9afd5231d5..5ed5cfc2b280 100644
> > --- a/drivers/infiniband/sw/rdmavt/mr.c
> > +++ b/drivers/infiniband/sw/rdmavt/mr.c
> > @@ -348,13 +348,13 @@ struct ib_mr *rvt_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
> >  
> >  	umem = ib_umem_get(pd->device, start, length, mr_access_flags);
> >  	if (IS_ERR(umem))
> > -		return (void *)umem;
> > +		return ERR_CAST(umem);
> >  
> >  	n = ib_umem_num_pages(umem);
> >  
> >  	mr = __rvt_alloc_mr(n, pd);
> >  	if (IS_ERR(mr)) {
> > -		ret = (struct ib_mr *)mr;
> > +		ret = ERR_CAST(mr);
> >  		goto bail_umem;
> >  	}
> >  
> > @@ -542,7 +542,7 @@ struct ib_mr *rvt_alloc_mr(struct ib_pd *pd, enum ib_mr_type mr_type,
> >  
> >  	mr = __rvt_alloc_mr(max_num_sg, pd);
> >  	if (IS_ERR(mr))
> > -		return (struct ib_mr *)mr;
> > +		return ERR_CAST(mr);
> >  
> >  	return &mr->ibmr;
> >  }
> 
> I don't think this is really necessary. You are not making the code more
> readable. It doesn't simplify things. So I'm not going to Ack it, but I won't
> Nak either.

I will take it because ERR_CAST is slightly better way to return error pointers.

Thanks

> 
> -Denny