diff options
Diffstat (limited to 'arch/um/drivers')
| -rw-r--r-- | arch/um/drivers/net_kern.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/arch/um/drivers/net_kern.c b/arch/um/drivers/net_kern.c index 59811cc880e..8c01fa81a1a 100644 --- a/arch/um/drivers/net_kern.c +++ b/arch/um/drivers/net_kern.c @@ -34,6 +34,46 @@ static inline void set_ether_mac(struct net_device *dev, unsigned char *addr) static DEFINE_SPINLOCK(opened_lock); static LIST_HEAD(opened); +/* + * The drop_skb is used when we can't allocate an skb. The + * packet is read into drop_skb in order to get the data off the + * connection to the host. + * It is reallocated whenever a maximum packet size is seen which is + * larger than any seen before. update_drop_skb is called from + * eth_configure when a new interface is added. + */ +static DEFINE_SPINLOCK(drop_lock); +static struct sk_buff *drop_skb; +static int drop_max; + +static int update_drop_skb(int max) +{ + struct sk_buff *new; + unsigned long flags; + int err = 0; + + spin_lock_irqsave(&drop_lock, flags); + + if (max <= drop_max) + goto out; + + err = -ENOMEM; + new = dev_alloc_skb(max); + if (new == NULL) + goto out; + + skb_put(new, max); + + kfree_skb(drop_skb); + drop_skb = new; + drop_max = max; + err = 0; +out: + spin_unlock_irqrestore(&drop_lock, flags); + + return err; +} + static int uml_net_rx(struct net_device *dev) { struct uml_net_private *lp = dev->priv; @@ -43,6 +83,9 @@ static int uml_net_rx(struct net_device *dev) /* If we can't allocate memory, try again next round. */ skb = dev_alloc_skb(lp->max_packet); if (skb == NULL) { + drop_skb->dev = dev; + /* Read a packet into drop_skb and don't do anything with it. */ + (*lp->read)(lp->fd, drop_skb, lp); lp->stats.rx_dropped++; return 0; } @@ -447,6 +490,10 @@ static void eth_configure(int n, void *init, char *mac, dev->watchdog_timeo = (HZ >> 1); dev->irq = UM_ETH_IRQ; + err = update_drop_skb(lp->max_packet); + if (err) + goto out_undo_user_init; + rtnl_lock(); err = register_netdevice(dev); rtnl_unlock(); |