Hello Bernard Metzler,
The patch cf049bb31f71: "RDMA/siw: Fix SQ/RQ drain logic" from Oct 4,
2019, leads to the following static checker warning:
drivers/infiniband/sw/siw/siw_verbs.c:1079 siw_post_receive()
error: locking inconsistency. We assume 'read_sem:&qp->state_lock' is both locked and unlocked at the start.
drivers/infiniband/sw/siw/siw_verbs.c
978 int siw_post_receive(struct ib_qp *base_qp, const struct ib_recv_wr *wr,
979 const struct ib_recv_wr **bad_wr)
980 {
981 struct siw_qp *qp = to_siw_qp(base_qp);
982 unsigned long flags;
983 int rv = 0;
984
985 if (qp->srq) {
986 *bad_wr = wr;
987 return -EOPNOTSUPP; /* what else from errno.h? */
988 }
989 if (!qp->kernel_verbs) {
990 siw_dbg_qp(qp, "no kernel post_recv for user mapped sq\n");
991 up_read(&qp->state_lock);
^^^^^^^^^^^^^^^^^^^^^^^^
The patch changes the locking so this isn't held here and should be
released. Should it be held, though?
992 *bad_wr = wr;
993 return -EINVAL;
994 }
995
996 /*
997 * Try to acquire QP state lock. Must be non-blocking
998 * to accommodate kernel clients needs.
999 */
1000 if (!down_read_trylock(&qp->state_lock)) {
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1001 if (qp->attrs.state == SIW_QP_STATE_ERROR) {
1002 /*
1003 * ERROR state is final, so we can be sure
1004 * this state will not change as long as the QP
1005 * exists.
1006 *
1007 * This handles an ib_drain_rq() call with
1008 * a concurrent request to set the QP state
1009 * to ERROR.
1010 */
1011 rv = siw_rq_flush_wr(qp, wr, bad_wr);
1012 } else {
regards,
dan carpenter
