RDMA/cxgb3: Make iwch_poll_cq_one() easier to analyze

Introduce the function __iwch_poll_cq_one() to make iwch_poll_cq_one()
easier to analyze for static source code analyzers. This patch avoids
that sparse reports the following:

drivers/infiniband/hw/cxgb3/iwch_cq.c:187:9: warning: context imbalance in 'iwch_poll_cq_one' - different lock contexts for basic block

Compile-tested only.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Steve Wise <swise@chelsio.com>
Acked-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/hw/cxgb3/iwch_cq.c

@@ -32,38 +32,16 @@
 #include "iwch_provider.h"
 #include "iwch.h"
 
-/*
- * Get one cq entry from cxio and map it to openib.
- *
- * Returns:
- *	0			EMPTY;
- *	1			cqe returned
- *	-EAGAIN		caller must try again
- *	any other -errno	fatal error
- */
-static int iwch_poll_cq_one(struct iwch_dev *rhp, struct iwch_cq *chp,
-			    struct ib_wc *wc)
+static int __iwch_poll_cq_one(struct iwch_dev *rhp, struct iwch_cq *chp,
+			      struct iwch_qp *qhp, struct ib_wc *wc)
 {
-	struct iwch_qp *qhp = NULL;
-	struct t3_cqe cqe, *rd_cqe;
-	struct t3_wq *wq;
+	struct t3_wq *wq = qhp ? &qhp->wq : NULL;
+	struct t3_cqe cqe;
 	u32 credit = 0;
 	u8 cqe_flushed;
 	u64 cookie;
 	int ret = 1;
 
-	rd_cqe = cxio_next_cqe(&chp->cq);
-
-	if (!rd_cqe)
-		return 0;
-
-	qhp = get_qhp(rhp, CQE_QPID(*rd_cqe));
-	if (!qhp)
-		wq = NULL;
-	else {
-		spin_lock(&qhp->lock);
-		wq = &(qhp->wq);
-	}
 	ret = cxio_poll_cq(wq, &(chp->cq), &cqe, &cqe_flushed, &cookie,
 				   &credit);
 	if (t3a_device(chp->rhp) && credit) {
@@ -79,7 +57,7 @@ static int iwch_poll_cq_one(struct iwch_dev *rhp, struct iwch_cq *chp,
 	ret = 1;
 
 	wc->wr_id = cookie;
-	wc->qp = &qhp->ibqp;
+	wc->qp = qhp ? &qhp->ibqp : NULL;
 	wc->vendor_err = CQE_STATUS(cqe);
 	wc->wc_flags = 0;
 
@@ -182,8 +160,38 @@ static int iwch_poll_cq_one(struct iwch_dev *rhp, struct iwch_cq *chp,
 		}
 	}
 out:
-	if (wq)
+	return ret;
+}
+
+/*
+ * Get one cq entry from cxio and map it to openib.
+ *
+ * Returns:
+ *	0			EMPTY;
+ *	1			cqe returned
+ *	-EAGAIN		caller must try again
+ *	any other -errno	fatal error
+ */
+static int iwch_poll_cq_one(struct iwch_dev *rhp, struct iwch_cq *chp,
+			    struct ib_wc *wc)
+{
+	struct iwch_qp *qhp;
+	struct t3_cqe *rd_cqe;
+	int ret;
+
+	rd_cqe = cxio_next_cqe(&chp->cq);
+
+	if (!rd_cqe)
+		return 0;
+
+	qhp = get_qhp(rhp, CQE_QPID(*rd_cqe));
+	if (qhp) {
+		spin_lock(&qhp->lock);
+		ret = __iwch_poll_cq_one(rhp, chp, qhp, wc);
 		spin_unlock(&qhp->lock);
+	} else {
+		ret = __iwch_poll_cq_one(rhp, chp, NULL, wc);
+	}
 	return ret;
 }