s390/qdio: restrict QAOB usage to IQD unicast queues

The IQD mcast queue doesn't support QAOB mode, so skip the
qdio_enable_async_operation() setup call for this queue. This avoids
the allocation of an unneeded QAOB pointer array, and sets up q->use_cq
properly so that drivers are prohibited from using QAOBs for mcast
traffic.

Take this opportunity to streamline the q->use_cq and aob != 0 checks.
The path to qdio_siga_output() is straight-forward, we don't need to
worry about being called with bad operands.
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

drivers/s390/cio/qdio_main.c

@@ -319,9 +319,7 @@ static int qdio_siga_output(struct qdio_q *q, unsigned int *busy_bit,
 	int retries = 0, cc;
 	unsigned long laob = 0;
 
-	WARN_ON_ONCE(aob && ((queue_type(q) != QDIO_IQDIO_QFMT) ||
-			     !q->u.out.use_cq));
-	if (q->u.out.use_cq && aob != 0) {
+	if (aob) {
 		fc = QDIO_SIGA_WRITEQ;
 		laob = aob;
 	}
@@ -621,9 +619,6 @@ static inline unsigned long qdio_aob_for_buffer(struct qdio_output_q *q,
 {
 	unsigned long phys_aob = 0;
 
-	if (!q->use_cq)
-		return 0;
-
 	if (!q->aobs[bufnr]) {
 		struct qaob *aob = qdio_allocate_aob();
 		q->aobs[bufnr] = aob;
@@ -1308,6 +1303,8 @@ static void qdio_detect_hsicq(struct qdio_irq *irq_ptr)
 
 	for_each_output_queue(irq_ptr, q, i) {
 		if (use_cq) {
+			if (multicast_outbound(q))
+				continue;
 			if (qdio_enable_async_operation(&q->u.out) < 0) {
 				use_cq = 0;
 				continue;
@@ -1553,6 +1550,7 @@ static int handle_outbound(struct qdio_q *q, unsigned int callflags,
 		/* One SIGA-W per buffer required for unicast HSI */
 		WARN_ON_ONCE(count > 1 && !multicast_outbound(q));
 
+		if (q->u.out.use_cq)
 			phys_aob = qdio_aob_for_buffer(&q->u.out, bufnr);
 
 		rc = qdio_kick_outbound_q(q, phys_aob);