Re: [PATCH rdma-next] RDMA/cxgb4: Remove unnecessary conversion from __be32 to cpu format

Leon Romanovsky
2017-10-24T18:59:56Z

[-- Attachment #1: Type: text/plain, Size: 2531 bytes --]

On Tue, Oct 24, 2017 at 01:42:16PM -0500, Steve Wise wrote:
> >
> > The scqe.stag is actually declared in u32 format and don't need
> > conversion from __be32 to cpu format.
> >
> > Remove the be32_to_cpu() and avoid the following sparse error.
> > drivers/infiniband/hw/cxgb4/cq.c:754:52: warning: cast to restricted __be32
> >
> > Cc: Steve Wise <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>
> > Signed-off-by: Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> > ---
> > drivers/infiniband/hw/cxgb4/t4.h | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/infiniband/hw/cxgb4/t4.h
> b/drivers/infiniband/hw/cxgb4/t4.h
> > index 2b44fa850bbb..a16f3596f5a8 100644
> > --- a/drivers/infiniband/hw/cxgb4/t4.h
> > +++ b/drivers/infiniband/hw/cxgb4/t4.h
> > @@ -234,7 +234,7 @@ struct t4_cqe {
> >
> > /* used for SQ completion processing */
> > #define CQE_WRID_SQ_IDX(x) ((x)->u.scqe.cidx)
> > -#define CQE_WRID_FR_STAG(x) (be32_to_cpu((x)->u.scqe.stag))
> > +#define CQE_WRID_FR_STAG(x) ((x)->u.scqe.stag)
>
> This is incorrect. The stag is filled in by HW which is BE. The declaration of
> scqe.stag needs to be __be32.

So why do you declare stag as u32?

drivers/infiniband/hw/cxgb4/cq.c:
676 static int c4iw_poll_cq_one(struct c4iw_cq *chp, struct ib_wc *wc)
...
679 struct t4_cqe uninitialized_var(cqe), *rd_cqe;
...
753 c4iw_invalidate_mr(qhp->rhp,
754 CQE_WRID_FR_STAG(&cqe));

....
drivers/infiniband/hw/cxgb4/t4.h:
162 /*
163 * CQE defs
164 */
165 struct t4_cqe {
166 __be32 header;
167 __be32 len;
168 union {
169 struct {
170 __be32 stag;
171 __be32 msn;
172 } rcqe;
173 struct {
174 u32 stag;
175 u16 nada2;
176 u16 cidx;
177 } scqe;
178 struct {
179 __be32 wrid_hi;
180 __be32 wrid_low;
181 } gen;
182 u64 drain_cookie;
183 } u;
184 __be64 reserved;
185 __be64 bits_type_ts;
186 };

Thanks

>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]