nfp: fix ethtool stats gather retry

The while loop fetching 64 bit ethtool statistics may have
to retry multiple times, it shouldn't modify the outside state.

Fixes: 4c3523623dc0 ("net: add driver for Netronome NFP4000/NFP6000 NIC VFs")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c b/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c
index 07969f0..dc016df 100644 (file)
--- a/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c
@@ -464,7 +464,7 @@ static u64 *nfp_vnic_get_sw_stats(struct net_device *netdev, u64 *data)
 
                do {
                        start = u64_stats_fetch_begin(&nn->r_vecs[i].rx_sync);
-                       *data++ = nn->r_vecs[i].rx_pkts;
+                       data[0] = nn->r_vecs[i].rx_pkts;
                        tmp[0] = nn->r_vecs[i].hw_csum_rx_ok;
                        tmp[1] = nn->r_vecs[i].hw_csum_rx_inner_ok;
                        tmp[2] = nn->r_vecs[i].hw_csum_rx_error;
@@ -472,14 +472,16 @@ static u64 *nfp_vnic_get_sw_stats(struct net_device *netdev, u64 *data)
 
                do {
                        start = u64_stats_fetch_begin(&nn->r_vecs[i].tx_sync);
-                       *data++ = nn->r_vecs[i].tx_pkts;
-                       *data++ = nn->r_vecs[i].tx_busy;
+                       data[1] = nn->r_vecs[i].tx_pkts;
+                       data[2] = nn->r_vecs[i].tx_busy;
                        tmp[3] = nn->r_vecs[i].hw_csum_tx;
                        tmp[4] = nn->r_vecs[i].hw_csum_tx_inner;
                        tmp[5] = nn->r_vecs[i].tx_gather;
                        tmp[6] = nn->r_vecs[i].tx_lso;
                } while (u64_stats_fetch_retry(&nn->r_vecs[i].tx_sync, start));
 
+               data += 3;
+
                for (j = 0; j < NN_ET_RVEC_GATHER_STATS; j++)
                        gathered_stats[j] += tmp[j];
        }