[PATCH] bonding: fix an oops when slave device does not provide get_stats

Bonding driver unconditionnaly dereference get_stats function pointer
for each of its slave device. This patch
- adds a check for NULL dev->get_stats pointer in bond_get_stats
- prints a notice when the bonding device enslave a device without
  get_stats function.

Signed-off-by: Laurent Riffard <laurent.riffard@free.fr>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 36 insertions, 27 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 17a461152d39..488d8ed9e740 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1336,6 +1336,13 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
                 goto err_undo_flags;
         }
 
+        if (slave_dev->get_stats == NULL) {
+                printk(KERN_NOTICE DRV_NAME
+                        ": %s: the driver for slave device %s does not provide "
+                        "get_stats function, network statistics will be "
+                        "inaccurate.\n", bond_dev->name, slave_dev->name);
+        }
+
         new_slave = kmalloc(sizeof(struct slave), GFP_KERNEL);
         if (!new_slave) {
                 res = -ENOMEM;
@@ -3605,33 +3612,35 @@ static struct net_device_stats *bond_get_stats(struct net_device *bond_dev)
         read_lock_bh(&bond->lock);
 
         bond_for_each_slave(bond, slave, i) {
-                sstats = slave->dev->get_stats(slave->dev);
-
-                stats->rx_packets += sstats->rx_packets;
-                stats->rx_bytes += sstats->rx_bytes;
-                stats->rx_errors += sstats->rx_errors;
-                stats->rx_dropped += sstats->rx_dropped;
-
-                stats->tx_packets += sstats->tx_packets;
-                stats->tx_bytes += sstats->tx_bytes;
-                stats->tx_errors += sstats->tx_errors;
-                stats->tx_dropped += sstats->tx_dropped;
-
-                stats->multicast += sstats->multicast;
-                stats->collisions += sstats->collisions;
-
-                stats->rx_length_errors += sstats->rx_length_errors;
-                stats->rx_over_errors += sstats->rx_over_errors;
-                stats->rx_crc_errors += sstats->rx_crc_errors;
-                stats->rx_frame_errors += sstats->rx_frame_errors;
-                stats->rx_fifo_errors += sstats->rx_fifo_errors;
-                stats->rx_missed_errors += sstats->rx_missed_errors;
-
-                stats->tx_aborted_errors += sstats->tx_aborted_errors;
-                stats->tx_carrier_errors += sstats->tx_carrier_errors;
-                stats->tx_fifo_errors += sstats->tx_fifo_errors;
-                stats->tx_heartbeat_errors += sstats->tx_heartbeat_errors;
-                stats->tx_window_errors += sstats->tx_window_errors;
+                if (slave->dev->get_stats) {
+                        sstats = slave->dev->get_stats(slave->dev);
+
+                        stats->rx_packets += sstats->rx_packets;
+                        stats->rx_bytes += sstats->rx_bytes;
+                        stats->rx_errors += sstats->rx_errors;
+                        stats->rx_dropped += sstats->rx_dropped;
+
+                        stats->tx_packets += sstats->tx_packets;
+                        stats->tx_bytes += sstats->tx_bytes;
+                        stats->tx_errors += sstats->tx_errors;
+                        stats->tx_dropped += sstats->tx_dropped;
+
+                        stats->multicast += sstats->multicast;
+                        stats->collisions += sstats->collisions;
+
+                        stats->rx_length_errors += sstats->rx_length_errors;
+                        stats->rx_over_errors += sstats->rx_over_errors;
+                        stats->rx_crc_errors += sstats->rx_crc_errors;
+                        stats->rx_frame_errors += sstats->rx_frame_errors;
+                        stats->rx_fifo_errors += sstats->rx_fifo_errors;
+                        stats->rx_missed_errors += sstats->rx_missed_errors;
+
+                        stats->tx_aborted_errors += sstats->tx_aborted_errors;
+                        stats->tx_carrier_errors += sstats->tx_carrier_errors;
+                        stats->tx_fifo_errors += sstats->tx_fifo_errors;
+                        stats->tx_heartbeat_errors += sstats->tx_heartbeat_errors;
+                        stats->tx_window_errors += sstats->tx_window_errors;
+                }
         }
 
         read_unlock_bh(&bond->lock);