bnxt_en: Improve RX buffer error handling.

When hardware reports RX buffer errors, the latest 57500 chips do not
require reset.  The packet is discarded by the hardware and the
ring will continue to operate.

Also, add an rx_buf_errors counter for this type of error.  It can help
the user to identify if the aggregation ring is too small.
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

@@ -1767,8 +1767,12 @@ static int bnxt_rx_pkt(struct bnxt *bp, struct bnxt_cp_ring_info *cpr,
 
 		rc = -EIO;
 		if (rx_err & RX_CMPL_ERRORS_BUFFER_ERROR_MASK) {
-			netdev_warn(bp->dev, "RX buffer error %x\n", rx_err);
-			bnxt_sched_reset(bp, rxr);
+			bnapi->cp_ring.rx_buf_errors++;
+			if (!(bp->flags & BNXT_FLAG_CHIP_P5)) {
+				netdev_warn(bp->dev, "RX buffer error %x\n",
+					    rx_err);
+				bnxt_sched_reset(bp, rxr);
+			}
 		}
 		goto next_rx_no_len;
 	}

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -932,6 +932,7 @@ struct bnxt_cp_ring_info {
 	dma_addr_t		hw_stats_map;
 	u32			hw_stats_ctx_id;
 	u64			rx_l4_csum_errors;
+	u64			rx_buf_errors;
 	u64			missed_irqs;
 
 	struct bnxt_ring_struct	cp_ring_struct;

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

@@ -173,6 +173,7 @@ static const char * const bnxt_ring_tpa2_stats_str[] = {
 
 static const char * const bnxt_ring_sw_stats_str[] = {
 	"rx_l4_csum_errors",
+	"rx_buf_errors",
 	"missed_irqs",
 };
 
@@ -552,6 +553,7 @@ static void bnxt_get_ethtool_stats(struct net_device *dev,
 		for (k = 0; k < stat_fields; j++, k++)
 			buf[j] = le64_to_cpu(hw_stats[k]);
 		buf[j++] = cpr->rx_l4_csum_errors;
+		buf[j++] = cpr->rx_buf_errors;
 		buf[j++] = cpr->missed_irqs;
 
 		bnxt_sw_func_stats[RX_TOTAL_DISCARDS].counter +=