IB/hfi1: Correct error calldown locking

The resource specific wait locking missed correcting the lock
for the notify_error_qp() calldown.

The code is fixed to correctly use the iowait lock field to protect
the head that is protected by that lock.

Fixes: Commit 4e045572 ("IB/hfi1: Add unique txwait_lock for txreq events")
Reviewed-by: Sebastian Sanchez <sebastian.sanchez@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/hfi1/qp.c

@@ -961,17 +961,20 @@ int get_pmtu_from_attr(struct rvt_dev_info *rdi, struct rvt_qp *qp,
 
 void notify_error_qp(struct rvt_qp *qp)
 {
-	struct hfi1_ibdev *dev = to_idev(qp->ibqp.device);
 	struct hfi1_qp_priv *priv = qp->priv;
+	seqlock_t *lock = priv->s_iowait.lock;
 
-	write_seqlock(&dev->iowait_lock);
-	if (!list_empty(&priv->s_iowait.list) && !(qp->s_flags & RVT_S_BUSY)) {
+	if (lock) {
+		write_seqlock(lock);
+		if (!list_empty(&priv->s_iowait.list) &&
+		    !(qp->s_flags & RVT_S_BUSY)) {
 			qp->s_flags &= ~RVT_S_ANY_WAIT_IO;
 			list_del_init(&priv->s_iowait.list);
 			priv->s_iowait.lock = NULL;
 			rvt_put_qp(qp);
 		}
-	write_sequnlock(&dev->iowait_lock);
+		write_sequnlock(lock);
+	}
 
 	if (!(qp->s_flags & RVT_S_BUSY)) {
 		qp->s_hdrwords = 0;