IB/hfi1: Move QOS decision logic into its own function

The decision to use QOS affects other resource allocation.
Move the QOS decision logic into its own function so it can
be called by other interested parties.
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/staging/rdma/hfi1/chip.c

@@ -13466,6 +13466,50 @@ static void complete_rsm_map_table(struct hfi1_devdata *dd,
 	}
 }
 
+/* return the number of RSM map table entries that will be used for QOS */
+static int qos_rmt_entries(struct hfi1_devdata *dd, unsigned int *mp,
+			   unsigned int *np)
+{
+	int i;
+	unsigned int m, n;
+	u8 max_by_vl = 0;
+
+	/* is QOS active at all? */
+	if (dd->n_krcv_queues <= MIN_KERNEL_KCTXTS ||
+	    num_vls == 1 ||
+	    krcvqsset <= 1)
+		goto no_qos;
+
+	/* determine bits for qpn */
+	for (i = 0; i < min_t(unsigned int, num_vls, krcvqsset); i++)
+		if (krcvqs[i] > max_by_vl)
+			max_by_vl = krcvqs[i];
+	if (max_by_vl > 32)
+		goto no_qos;
+	m = ilog2(__roundup_pow_of_two(max_by_vl));
+
+	/* determine bits for vl */
+	n = ilog2(__roundup_pow_of_two(num_vls));
+
+	/* reject if too much is used */
+	if ((m + n) > 7)
+		goto no_qos;
+
+	if (mp)
+		*mp = m;
+	if (np)
+		*np = n;
+
+	return 1 << (m + n);
+
+no_qos:
+	if (mp)
+		*mp = 0;
+	if (np)
+		*np = 0;
+	return 0;
+}
+
 /**
  * init_qos - init RX qos
  * @dd - device data
@@ -13482,33 +13526,22 @@ static void complete_rsm_map_table(struct hfi1_devdata *dd,
  */
 static void init_qos(struct hfi1_devdata *dd, struct rsm_map_table *rmt)
 {
-	u8 max_by_vl = 0;
 	unsigned qpns_per_vl, ctxt, i, qpn, n = 1, m;
 	unsigned int rmt_entries;
 	u64 reg;
 
-	/* validate */
-	if (!rmt ||
-	    dd->n_krcv_queues <= MIN_KERNEL_KCTXTS ||
-	    num_vls == 1 ||
-	    krcvqsset <= 1)
-		goto bail;
-	for (i = 0; i < min_t(unsigned, num_vls, krcvqsset); i++)
-		if (krcvqs[i] > max_by_vl)
-			max_by_vl = krcvqs[i];
-	if (max_by_vl > 32)
+	if (!rmt)
 		goto bail;
-	qpns_per_vl = __roundup_pow_of_two(max_by_vl);
-	/* determine bits vl */
-	n = ilog2(__roundup_pow_of_two(num_vls));
-	/* determine bits for qpn */
-	m = ilog2(qpns_per_vl);
-	if ((m + n) > 7)
+	rmt_entries = qos_rmt_entries(dd, &m, &n);
+	if (rmt_entries == 0)
 		goto bail;
+	qpns_per_vl = 1 << m;
+
 	/* enough room in the map table? */
 	rmt_entries = 1 << (m + n);
 	if (rmt->used + rmt_entries >= NUM_MAP_ENTRIES)
 		goto bail;
+
 	/* add qos entries to the the RSM map table */
 	for (i = 0, ctxt = FIRST_KERNEL_KCTXT; i < num_vls; i++) {
 		unsigned tctxt;