bnxt_en: Do not free port statistics buffer when device is down.

Port statistics which include RDMA counters are useful even when the
netdevice is down.  Do not free the port statistics DMA buffers
when the netdevice is down.  This is keep the snapshot of the port
statistics and counters will just continue counting when the
netdevice goes back up.

Split the bnxt_free_stats() function into 2 functions.  The port
statistics buffers will only be freed when the netdevice is
removed.
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

@@ -3320,9 +3320,8 @@ static int bnxt_alloc_hwrm_short_cmd_req(struct bnxt *bp)
 	return 0;
 }
 
-static void bnxt_free_stats(struct bnxt *bp)
+static void bnxt_free_port_stats(struct bnxt *bp)
 {
-	u32 size, i;
 	struct pci_dev *pdev = bp->pdev;
 
 	bp->flags &= ~BNXT_FLAG_PORT_STATS;
@@ -3348,6 +3347,12 @@ static void bnxt_free_stats(struct bnxt *bp)
 				  bp->hw_rx_port_stats_ext_map);
 		bp->hw_rx_port_stats_ext = NULL;
 	}
+}
+
+static void bnxt_free_ring_stats(struct bnxt *bp)
+{
+	struct pci_dev *pdev = bp->pdev;
+	int size, i;
 
 	if (!bp->bnapi)
 		return;
@@ -3387,6 +3392,9 @@ static int bnxt_alloc_stats(struct bnxt *bp)
 	}
 
 	if (BNXT_PF(bp) && bp->chip_num != CHIP_NUM_58700) {
+		if (bp->hw_rx_port_stats)
+			goto alloc_ext_stats;
+
 		bp->hw_port_stats_size = sizeof(struct rx_port_stats) +
 					 sizeof(struct tx_port_stats) + 1024;
 
@@ -3403,11 +3411,15 @@ static int bnxt_alloc_stats(struct bnxt *bp)
 					   sizeof(struct rx_port_stats) + 512;
 		bp->flags |= BNXT_FLAG_PORT_STATS;
 
+alloc_ext_stats:
 		/* Display extended statistics only if FW supports it */
 		if (bp->hwrm_spec_code < 0x10804 ||
 		    bp->hwrm_spec_code == 0x10900)
 			return 0;
 
+		if (bp->hw_rx_port_stats_ext)
+			goto alloc_tx_ext_stats;
+
 		bp->hw_rx_port_stats_ext =
 			dma_zalloc_coherent(&pdev->dev,
 					    sizeof(struct rx_port_stats_ext),
@@ -3416,6 +3428,10 @@ static int bnxt_alloc_stats(struct bnxt *bp)
 		if (!bp->hw_rx_port_stats_ext)
 			return 0;
 
+alloc_tx_ext_stats:
+		if (bp->hw_tx_port_stats_ext)
+			return 0;
+
 		if (bp->hwrm_spec_code >= 0x10902) {
 			bp->hw_tx_port_stats_ext =
 				dma_zalloc_coherent(&pdev->dev,
@@ -3523,7 +3539,7 @@ static void bnxt_free_mem(struct bnxt *bp, bool irq_re_init)
 	bnxt_free_cp_rings(bp);
 	bnxt_free_ntp_fltrs(bp, irq_re_init);
 	if (irq_re_init) {
-		bnxt_free_stats(bp);
+		bnxt_free_ring_stats(bp);
 		bnxt_free_ring_grps(bp);
 		bnxt_free_vnics(bp);
 		kfree(bp->tx_ring_map);
@@ -9864,6 +9880,7 @@ static void bnxt_remove_one(struct pci_dev *pdev)
 	kfree(bp->ctx);
 	bp->ctx = NULL;
 	bnxt_cleanup_pci(bp);
+	bnxt_free_port_stats(bp);
 	free_netdev(dev);
 }
 

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

@@ -433,8 +433,10 @@ static void bnxt_get_ethtool_stats(struct net_device *dev,
 	struct bnxt *bp = netdev_priv(dev);
 	u32 stat_fields = sizeof(struct ctx_hw_stats) / 8;
 
-	if (!bp->bnapi)
-		return;
+	if (!bp->bnapi) {
+		j += BNXT_NUM_STATS * bp->cp_nr_rings + BNXT_NUM_SW_FUNC_STATS;
+		goto skip_ring_stats;
+	}
 
 	for (i = 0; i < BNXT_NUM_SW_FUNC_STATS; i++)
 		bnxt_sw_func_stats[i].counter = 0;
@@ -459,6 +461,7 @@ static void bnxt_get_ethtool_stats(struct net_device *dev,
 	for (i = 0; i < BNXT_NUM_SW_FUNC_STATS; i++, j++)
 		buf[j] = bnxt_sw_func_stats[i].counter;
 
+skip_ring_stats:
 	if (bp->flags & BNXT_FLAG_PORT_STATS) {
 		__le64 *port_stats = (__le64 *)bp->hw_rx_port_stats;