diff options
| -rw-r--r-- | include/linux/netdevice.h | 43 | ||||
| -rw-r--r-- | net/core/dev.c | 32 | ||||
| -rw-r--r-- | net/sched/sch_generic.c | 9 |
3 files changed, 66 insertions, 18 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 083b5989cec..8b266390b9e 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -63,27 +63,48 @@ struct wireless_dev; #define HAVE_FREE_NETDEV /* free_netdev() */ #define HAVE_NETDEV_PRIV /* netdev_priv() */ -#define NET_XMIT_SUCCESS 0 -#define NET_XMIT_DROP 1 /* skb dropped */ -#define NET_XMIT_CN 2 /* congestion notification */ -#define NET_XMIT_POLICED 3 /* skb is shot by police */ -#define NET_XMIT_MASK 0xFFFF /* qdisc flags in net/sch_generic.h */ +/* + * Transmit return codes: transmit return codes originate from three different + * namespaces: + * + * - qdisc return codes + * - driver transmit return codes + * - errno values + * + * Drivers are allowed to return any one of those in their hard_start_xmit() + * function. Real network devices commonly used with qdiscs should only return + * the driver transmit return codes though - when qdiscs are used, the actual + * transmission happens asynchronously, so the value is not propagated to + * higher layers. Virtual network devices transmit synchronously, in this case + * the driver transmit return codes are consumed by dev_queue_xmit(), all + * others are propagated to higher layers. + */ + +/* qdisc ->enqueue() return codes. */ +#define NET_XMIT_SUCCESS 0x00 +#define NET_XMIT_DROP 0x10 /* skb dropped */ +#define NET_XMIT_CN 0x20 /* congestion notification */ +#define NET_XMIT_POLICED 0x30 /* skb is shot by police */ +#define NET_XMIT_MASK 0xf0 /* qdisc flags in net/sch_generic.h */ /* Backlog congestion levels */ -#define NET_RX_SUCCESS 0 /* keep 'em coming, baby */ -#define NET_RX_DROP 1 /* packet dropped */ +#define NET_RX_SUCCESS 0 /* keep 'em coming, baby */ +#define NET_RX_DROP 1 /* packet dropped */ /* NET_XMIT_CN is special. It does not guarantee that this packet is lost. It * indicates that the device will soon be dropping packets, or already drops * some packets of the same priority; prompting us to send less aggressively. */ -#define net_xmit_eval(e) ((e) == NET_XMIT_CN? 0 : (e)) +#define net_xmit_eval(e) ((e) == NET_XMIT_CN ? 0 : (e)) #define net_xmit_errno(e) ((e) != NET_XMIT_CN ? -ENOBUFS : 0) /* Driver transmit return codes */ +#define NETDEV_TX_MASK 0xf + enum netdev_tx { - NETDEV_TX_OK = 0, /* driver took care of packet */ - NETDEV_TX_BUSY, /* driver tx path was busy*/ - NETDEV_TX_LOCKED = -1, /* driver tx lock was already taken */ + __NETDEV_TX_MIN = INT_MIN, /* make sure enum is signed */ + NETDEV_TX_OK = 0, /* driver took care of packet */ + NETDEV_TX_BUSY = 1, /* driver tx path was busy*/ + NETDEV_TX_LOCKED = 2, /* driver tx lock was already taken */ }; typedef enum netdev_tx netdev_tx_t; diff --git a/net/core/dev.c b/net/core/dev.c index ad8e320ceba..548340b5729 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1757,7 +1757,7 @@ int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev, struct netdev_queue *txq) { const struct net_device_ops *ops = dev->netdev_ops; - int rc; + int rc = NETDEV_TX_OK; if (likely(!skb->next)) { if (!list_empty(&ptype_all)) @@ -1805,6 +1805,8 @@ gso: nskb->next = NULL; rc = ops->ndo_start_xmit(nskb, dev); if (unlikely(rc != NETDEV_TX_OK)) { + if (rc & ~NETDEV_TX_MASK) + goto out_kfree_gso_skb; nskb->next = skb->next; skb->next = nskb; return rc; @@ -1814,11 +1816,12 @@ gso: return NETDEV_TX_BUSY; } while (skb->next); - skb->destructor = DEV_GSO_CB(skb)->destructor; - +out_kfree_gso_skb: + if (likely(skb->next == NULL)) + skb->destructor = DEV_GSO_CB(skb)->destructor; out_kfree_skb: kfree_skb(skb); - return NETDEV_TX_OK; + return rc; } static u32 skb_tx_hashrnd; @@ -1906,6 +1909,23 @@ static inline int __dev_xmit_skb(struct sk_buff *skb, struct Qdisc *q, return rc; } +static inline bool dev_xmit_complete(int rc) +{ + /* successful transmission */ + if (rc == NETDEV_TX_OK) + return true; + + /* error while transmitting, driver consumed skb */ + if (rc < 0) + return true; + + /* error while queueing to a different device, driver consumed skb */ + if (rc & NET_XMIT_MASK) + return true; + + return false; +} + /** * dev_queue_xmit - transmit a buffer * @skb: buffer to transmit @@ -2003,8 +2023,8 @@ gso: HARD_TX_LOCK(dev, txq, cpu); if (!netif_tx_queue_stopped(txq)) { - rc = NET_XMIT_SUCCESS; - if (!dev_hard_start_xmit(skb, dev, txq)) { + rc = dev_hard_start_xmit(skb, dev, txq); + if (dev_xmit_complete(rc)) { HARD_TX_UNLOCK(dev, txq); goto out; } diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 4ae6aa562f2..b13821ad2fb 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -120,8 +120,15 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q, HARD_TX_LOCK(dev, txq, smp_processor_id()); if (!netif_tx_queue_stopped(txq) && - !netif_tx_queue_frozen(txq)) + !netif_tx_queue_frozen(txq)) { ret = dev_hard_start_xmit(skb, dev, txq); + + /* an error implies that the skb was consumed */ + if (ret < 0) + ret = NETDEV_TX_OK; + /* all NET_XMIT codes map to NETDEV_TX_OK */ + ret &= ~NET_XMIT_MASK; + } HARD_TX_UNLOCK(dev, txq); spin_lock(root_lock); |