bnxt_en: Don't reserve rings on VF when min rings were not provisioned by PF.

When rings are more limited and the PF has not provisioned minimum
guaranteed rings to the VF, do not reserve rings during driver probe.
Wait till device open before reserving rings when they will be used.
Device open will succeed if some minimum rings can be successfully
reserved and allocated.
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -5952,6 +5952,9 @@ static int bnxt_init_msix(struct bnxt *bp)
 	if (total_vecs > max)
 		total_vecs = max;
 
+	if (!total_vecs)
+		return 0;
+
 	msix_ent = kcalloc(total_vecs, sizeof(struct msix_entry), GFP_KERNEL);
 	if (!msix_ent)
 		return -ENOMEM;
@@ -7276,6 +7279,25 @@ static int bnxt_cfg_rx_mode(struct bnxt *bp)
 	return rc;
 }
 
+static bool bnxt_can_reserve_rings(struct bnxt *bp)
+{
+#ifdef CONFIG_BNXT_SRIOV
+	if ((bp->flags & BNXT_FLAG_NEW_RM) && BNXT_VF(bp)) {
+		struct bnxt_hw_resc *hw_resc = &bp->hw_resc;
+
+		/* No minimum rings were provisioned by the PF.  Don't
+		 * reserve rings by default when device is down.
+		 */
+		if (hw_resc->min_tx_rings || hw_resc->resv_tx_rings)
+			return true;
+
+		if (!netif_running(bp->dev))
+			return false;
+	}
+#endif
+	return true;
+}
+
 /* If the chip and firmware supports RFS */
 static bool bnxt_rfs_supported(struct bnxt *bp)
 {
@@ -7292,7 +7314,7 @@ static bool bnxt_rfs_capable(struct bnxt *bp)
 #ifdef CONFIG_RFS_ACCEL
 	int vnics, max_vnics, max_rss_ctxs;
 
-	if (!(bp->flags & BNXT_FLAG_MSIX_CAP))
+	if (!(bp->flags & BNXT_FLAG_MSIX_CAP) || !bnxt_can_reserve_rings(bp))
 		return false;
 
 	vnics = 1 + bp->rx_nr_rings;
@@ -8526,6 +8548,9 @@ static int bnxt_set_dflt_rings(struct bnxt *bp, bool sh)
 {
 	int dflt_rings, max_rx_rings, max_tx_rings, rc;
 
+	if (!bnxt_can_reserve_rings(bp))
+		return 0;
+
 	if (sh)
 		bp->flags |= BNXT_FLAG_SHARED_RINGS;
 	dflt_rings = netif_get_num_default_rss_queues();