sundance: get_stats proper locking

sundance get_stats() should not be run concurrently, add a lock to avoid
potential losses.

Note: Remove unused rx_lock field

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/net/sundance.c b/drivers/net/sundance.c
index 27d69aaba486..4283cc52a8c9 100644
--- a/drivers/net/sundance.c
+++ b/drivers/net/sundance.c
@@ -365,7 +365,6 @@ struct netdev_private {
         struct timer_list timer;                /* Media monitoring timer. */
         /* Frequently used values: keep some adjacent for cache effect. */
         spinlock_t lock;
-        spinlock_t rx_lock;                     /* Group with Tx control cache line. */
         int msg_enable;
         int chip_id;
         unsigned int cur_rx, dirty_rx;          /* Producer/consumer ring indices */
@@ -390,6 +389,7 @@ struct netdev_private {
         unsigned char phys[MII_CNT];            /* MII device addresses, only first one used. */
         struct pci_dev *pci_dev;
         void __iomem *base;
+        spinlock_t statlock;
 };
 
 /* The station address location in the EEPROM. */
@@ -514,6 +514,7 @@ static int __devinit sundance_probe1 (struct pci_dev *pdev,
         np->chip_id = chip_idx;
         np->msg_enable = (1 << debug) - 1;
         spin_lock_init(&np->lock);
+        spin_lock_init(&np->statlock);
         tasklet_init(&np->rx_tasklet, rx_poll, (unsigned long)dev);
         tasklet_init(&np->tx_tasklet, tx_poll, (unsigned long)dev);
 
@@ -1486,10 +1487,9 @@ static struct net_device_stats *get_stats(struct net_device *dev)
         struct netdev_private *np = netdev_priv(dev);
         void __iomem *ioaddr = np->base;
         int i;
+        unsigned long flags;
 
-        /* We should lock this segment of code for SMP eventually, although
-           the vulnerability window is very small and statistics are
-           non-critical. */
+        spin_lock_irqsave(&np->statlock, flags);
         /* The chip only need report frame silently dropped. */
         dev->stats.rx_missed_errors     += ioread8(ioaddr + RxMissed);
         dev->stats.tx_packets += ioread16(ioaddr + TxFramesOK);
@@ -1506,6 +1506,8 @@ static struct net_device_stats *get_stats(struct net_device *dev)
         dev->stats.rx_bytes += ioread16(ioaddr + RxOctetsLow);
         dev->stats.rx_bytes += ioread16(ioaddr + RxOctetsHigh) << 16;
 
+        spin_unlock_irqrestore(&np->statlock, flags);
+
         return &dev->stats;
 }