Re: linux-next: build warning after merge of the rdma tree

Bart Van Assche
2018-07-26T05:10:34Z

On Wed, 2018-07-25 at 21:05 -0600, Jason Gunthorpe wrote:
> On Thu, Jul 26, 2018 at 10:55:53AM +1000, Stephen Rothwell wrote:
> > Hi all,
> >
> > After merging the rdma tree, today's linux-next build (powerpc
> > ppc64_defconfig) produced this warning:
> >
> > net/sunrpc/xprtrdma/svc_rdma_rw.c: In function 'svc_rdma_post_chunk_ctxt':
> > net/sunrpc/xprtrdma/svc_rdma_rw.c:350:5: warning: 'bad_wr' may be used uninitialized in this function [-Wmaybe-uninitialized]
> > if (bad_wr != first_wr)
> > ^
>
> Huh. I'm quite surprised 0-day build service didn't warn on this.
>
> > Introduced by commit
> >
> > ed288d74a9e5 ("net/xprtrdma: Simplify ib_post_(send|recv|srq_recv)() calls")
> >
> > This is an actual problem.
>
> Yes, for sure. Bart?

Thanks Stephen for having reported this. I propose to revert the changes in
net/sunrpc/xprtrdma/svc_rdma_rw.c. Jason, do you want me to submit the below
as a formal patch?

Thanks,

Bart.

diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
index 80975427f523..ce3ea8419704 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
@@ -329,7 +329,7 @@ static int svc_rdma_post_chunk_ctxt(struct svc_rdma_chunk_ctxt *cc)
do {
if (atomic_sub_return(cc->cc_sqecount,
&rdma->sc_sq_avail) > 0) {
- ret = ib_post_send(rdma->sc_qp, first_wr, NULL);
+ ret = ib_post_send(rdma->sc_qp, first_wr, &bad_wr);
trace_svcrdma_post_rw(&cc->cc_cqe,
cc->cc_sqecount, ret);
if (ret)