bnx2x: Fixed MSI-X enabling flow

Try to enable less MSI-X vectors if initial request has failed.

Author: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Dmitry Kravkov <dmitry@broadcom.com>
Signed-off-by: Vladislav Zolotarov <vladz@broadcom.com>
Signed-off-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bnx2x.h

@@ -24,16 +24,25 @@
 #define BCM_VLAN			1
 #endif
 
+#define BNX2X_MULTI_QUEUE
+
+#define BNX2X_NEW_NAPI
+
+
+
 #if defined(CONFIG_CNIC) || defined(CONFIG_CNIC_MODULE)
 #define BCM_CNIC 1
 #include "cnic_if.h"
 #endif
 
-#define BNX2X_MULTI_QUEUE
-
-#define BNX2X_NEW_NAPI
-
 
+#ifdef BCM_CNIC
+#define BNX2X_MIN_MSIX_VEC_CNT 3
+#define BNX2X_MSIX_VEC_FP_START 2
+#else
+#define BNX2X_MIN_MSIX_VEC_CNT 2
+#define BNX2X_MSIX_VEC_FP_START 1
+#endif
 
 #include <linux/mdio.h>
 #include "bnx2x_reg.h"
@@ -862,7 +871,6 @@ struct bnx2x {
 #endif
 #define INT_MODE_INTx			1
 #define INT_MODE_MSI			2
-#define INT_MODE_MSIX			3
 
 	int			tx_ring_size;
 

drivers/net/bnx2x_main.c

@@ -7418,7 +7418,31 @@ static int bnx2x_enable_msix(struct bnx2x *bp)
 
 	rc = pci_enable_msix(bp->pdev, &bp->msix_table[0],
 			     BNX2X_NUM_QUEUES(bp) + offset);
-	if (rc) {
+
+	/*
+	 * reconfigure number of tx/rx queues according to available
+	 * MSI-X vectors
+	 */
+	if (rc >= BNX2X_MIN_MSIX_VEC_CNT) {
+		/* vectors available for FP */
+		int fp_vec = rc - BNX2X_MSIX_VEC_FP_START;
+
+		DP(NETIF_MSG_IFUP,
+		   "Trying to use less MSI-X vectors: %d\n", rc);
+
+		rc = pci_enable_msix(bp->pdev, &bp->msix_table[0], rc);
+
+		if (rc) {
+			DP(NETIF_MSG_IFUP,
+			   "MSI-X is not attainable  rc %d\n", rc);
+			return rc;
+		}
+
+		bp->num_queues = min(bp->num_queues, fp_vec);
+
+		DP(NETIF_MSG_IFUP, "New queue configuration set: %d\n",
+				  bp->num_queues);
+	} else if (rc) {
 		DP(NETIF_MSG_IFUP, "MSI-X is not attainable  rc %d\n", rc);
 		return rc;
 	}
@@ -7841,8 +7865,6 @@ static int bnx2x_set_num_queues(struct bnx2x *bp)
 		bp->num_queues = 1;
 		DP(NETIF_MSG_IFUP, "set number of queues to 1\n");
 		break;
-
-	case INT_MODE_MSIX:
 	default:
 		/* Set number of queues according to bp->multi_mode value */
 		bnx2x_set_num_queues_msix(bp);