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>

diff --git a/drivers/net/s2io.c b/drivers/net/s2io.c
index 86d77d0..a2b0730 100644 (file)
--- 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);