S2io: fix statistics flush after a MTU change

On s2io driver, when you change the interface MTU, it invokes a card
reset, which flush some statistics.  This patch solves this problem, and
also set the net_device->stats as the default statistics structure,
instead of s2io_nic->stats.

To do that, s2io_nic->stats turned into a staging area, where is saved
statistics of the last hardware statistics query. So, the difference
between the current hardware statistics and s2io_nic->stats, is the
value that should be summed up, in order to get the correct statistics
value, even after a reset.

Signed-off-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 23 insertions, 6 deletions

diff --git a/drivers/net/s2io.c b/drivers/net/s2io.c
index 86d77d05190a..a2b073097e5c 100644
--- a/drivers/net/s2io.c
+++ b/drivers/net/s2io.c
@@ -3143,7 +3143,7 @@ static void tx_intr_handler(struct fifo_info *fifo_data)
                 pkt_cnt++;
 
                 /* Updating the statistics block */
-                nic->stats.tx_bytes += skb->len;
+                nic->dev->stats.tx_bytes += skb->len;
                 nic->mac_control.stats_info->sw_stat.mem_freed += skb->truesize;
                 dev_kfree_skb_irq(skb);
 
@@ -4896,25 +4896,42 @@ static struct net_device_stats *s2io_get_stats(struct net_device *dev)
         /* Configure Stats for immediate updt */
         s2io_updt_stats(sp);
 
+        /* Using sp->stats as a staging area, because reset (due to mtu
+           change, for example) will clear some hardware counters */
+        dev->stats.tx_packets +=
+                le32_to_cpu(mac_control->stats_info->tmac_frms) - 
+                sp->stats.tx_packets;
         sp->stats.tx_packets =
                 le32_to_cpu(mac_control->stats_info->tmac_frms);
+        dev->stats.tx_errors +=
+                le32_to_cpu(mac_control->stats_info->tmac_any_err_frms) -
+                sp->stats.tx_errors;
         sp->stats.tx_errors =
                 le32_to_cpu(mac_control->stats_info->tmac_any_err_frms);
+        dev->stats.rx_errors +=
+                le64_to_cpu(mac_control->stats_info->rmac_drop_frms) -
+                sp->stats.rx_errors;
         sp->stats.rx_errors =
                 le64_to_cpu(mac_control->stats_info->rmac_drop_frms);
+        dev->stats.multicast =
+                le32_to_cpu(mac_control->stats_info->rmac_vld_mcst_frms) - 
+                sp->stats.multicast;
         sp->stats.multicast =
                 le32_to_cpu(mac_control->stats_info->rmac_vld_mcst_frms);
+        dev->stats.rx_length_errors =
+                le64_to_cpu(mac_control->stats_info->rmac_long_frms) - 
+                sp->stats.rx_length_errors;
         sp->stats.rx_length_errors =
                 le64_to_cpu(mac_control->stats_info->rmac_long_frms);
 
         /* collect per-ring rx_packets and rx_bytes */
-        sp->stats.rx_packets = sp->stats.rx_bytes = 0;
+        dev->stats.rx_packets = dev->stats.rx_bytes = 0;
         for (i = 0; i < config->rx_ring_num; i++) {
-                sp->stats.rx_packets += mac_control->rings[i].rx_packets;
-                sp->stats.rx_bytes += mac_control->rings[i].rx_bytes;
+                dev->stats.rx_packets += mac_control->rings[i].rx_packets;
+                dev->stats.rx_bytes += mac_control->rings[i].rx_bytes;
         }
 
-        return (&sp->stats);
+        return (&dev->stats);
 }
 
 /**
@@ -7419,7 +7436,7 @@ static int rx_osm_handler(struct ring_info *ring_data, struct RxD_t * rxdp)
                 if (err_mask != 0x5) {
                         DBG_PRINT(ERR_DBG, "%s: Rx error Value: 0x%x\n",
                                 dev->name, err_mask);
-                        sp->stats.rx_crc_errors++;
+                        dev->stats.rx_crc_errors++;
                         sp->mac_control.stats_info->sw_stat.mem_freed
                                 += skb->truesize;
                         dev_kfree_skb(skb);