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author | Cong Wang <xiyou.wangcong@gmail.com> | 2013-01-21 00:39:24 +0000 |
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committer | David S. Miller <davem@davemloft.net> | 2013-01-21 14:26:17 -0500 |
commit | 441d9d327f1e770f5aa76fd91735851ac6e1e236 (patch) | |
tree | f7a0a8d206d5745fd196bc9a5c98c2f8d67086ac /net/core/flow_dissector.c | |
parent | cd5f20461de8e3e9b04932e4ba3e37afe39b8898 (diff) | |
download | linux-stable-441d9d327f1e770f5aa76fd91735851ac6e1e236.tar.gz linux-stable-441d9d327f1e770f5aa76fd91735851ac6e1e236.tar.bz2 linux-stable-441d9d327f1e770f5aa76fd91735851ac6e1e236.zip |
net: move rx and tx hash functions to net/core/flow_dissector.c
__skb_tx_hash() and __skb_get_rxhash() are all for calculating hash
value based by some fields in skb, mostly used for selecting queues
by device drivers.
Meanwhile, net/core/dev.c is bloating.
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/flow_dissector.c')
-rw-r--r-- | net/core/flow_dissector.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 466820b6e344..9d4c7201400d 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -143,3 +143,176 @@ ipv6: return true; } EXPORT_SYMBOL(skb_flow_dissect); + +static u32 hashrnd __read_mostly; + +/* + * __skb_get_rxhash: calculate a flow hash based on src/dst addresses + * and src/dst port numbers. Sets rxhash in skb to non-zero hash value + * on success, zero indicates no valid hash. Also, sets l4_rxhash in skb + * if hash is a canonical 4-tuple hash over transport ports. + */ +void __skb_get_rxhash(struct sk_buff *skb) +{ + struct flow_keys keys; + u32 hash; + + if (!skb_flow_dissect(skb, &keys)) + return; + + if (keys.ports) + skb->l4_rxhash = 1; + + /* get a consistent hash (same value on both flow directions) */ + if (((__force u32)keys.dst < (__force u32)keys.src) || + (((__force u32)keys.dst == (__force u32)keys.src) && + ((__force u16)keys.port16[1] < (__force u16)keys.port16[0]))) { + swap(keys.dst, keys.src); + swap(keys.port16[0], keys.port16[1]); + } + + hash = jhash_3words((__force u32)keys.dst, + (__force u32)keys.src, + (__force u32)keys.ports, hashrnd); + if (!hash) + hash = 1; + + skb->rxhash = hash; +} +EXPORT_SYMBOL(__skb_get_rxhash); + +/* + * Returns a Tx hash based on the given packet descriptor a Tx queues' number + * to be used as a distribution range. + */ +u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb, + unsigned int num_tx_queues) +{ + u32 hash; + u16 qoffset = 0; + u16 qcount = num_tx_queues; + + if (skb_rx_queue_recorded(skb)) { + hash = skb_get_rx_queue(skb); + while (unlikely(hash >= num_tx_queues)) + hash -= num_tx_queues; + return hash; + } + + if (dev->num_tc) { + u8 tc = netdev_get_prio_tc_map(dev, skb->priority); + qoffset = dev->tc_to_txq[tc].offset; + qcount = dev->tc_to_txq[tc].count; + } + + if (skb->sk && skb->sk->sk_hash) + hash = skb->sk->sk_hash; + else + hash = (__force u16) skb->protocol; + hash = jhash_1word(hash, hashrnd); + + return (u16) (((u64) hash * qcount) >> 32) + qoffset; +} +EXPORT_SYMBOL(__skb_tx_hash); + +static inline u16 dev_cap_txqueue(struct net_device *dev, u16 queue_index) +{ + if (unlikely(queue_index >= dev->real_num_tx_queues)) { + net_warn_ratelimited("%s selects TX queue %d, but real number of TX queues is %d\n", + dev->name, queue_index, + dev->real_num_tx_queues); + return 0; + } + return queue_index; +} + +static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb) +{ +#ifdef CONFIG_XPS + struct xps_dev_maps *dev_maps; + struct xps_map *map; + int queue_index = -1; + + rcu_read_lock(); + dev_maps = rcu_dereference(dev->xps_maps); + if (dev_maps) { + map = rcu_dereference( + dev_maps->cpu_map[raw_smp_processor_id()]); + if (map) { + if (map->len == 1) + queue_index = map->queues[0]; + else { + u32 hash; + if (skb->sk && skb->sk->sk_hash) + hash = skb->sk->sk_hash; + else + hash = (__force u16) skb->protocol ^ + skb->rxhash; + hash = jhash_1word(hash, hashrnd); + queue_index = map->queues[ + ((u64)hash * map->len) >> 32]; + } + if (unlikely(queue_index >= dev->real_num_tx_queues)) + queue_index = -1; + } + } + rcu_read_unlock(); + + return queue_index; +#else + return -1; +#endif +} + +u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb) +{ + struct sock *sk = skb->sk; + int queue_index = sk_tx_queue_get(sk); + + if (queue_index < 0 || skb->ooo_okay || + queue_index >= dev->real_num_tx_queues) { + int new_index = get_xps_queue(dev, skb); + if (new_index < 0) + new_index = skb_tx_hash(dev, skb); + + if (queue_index != new_index && sk) { + struct dst_entry *dst = + rcu_dereference_check(sk->sk_dst_cache, 1); + + if (dst && skb_dst(skb) == dst) + sk_tx_queue_set(sk, queue_index); + + } + + queue_index = new_index; + } + + return queue_index; +} +EXPORT_SYMBOL(__netdev_pick_tx); + +struct netdev_queue *netdev_pick_tx(struct net_device *dev, + struct sk_buff *skb) +{ + int queue_index = 0; + + if (dev->real_num_tx_queues != 1) { + const struct net_device_ops *ops = dev->netdev_ops; + if (ops->ndo_select_queue) + queue_index = ops->ndo_select_queue(dev, skb); + else + queue_index = __netdev_pick_tx(dev, skb); + queue_index = dev_cap_txqueue(dev, queue_index); + } + + skb_set_queue_mapping(skb, queue_index); + return netdev_get_tx_queue(dev, queue_index); +} + +static int __init initialize_hashrnd(void) +{ + get_random_bytes(&hashrnd, sizeof(hashrnd)); + return 0; +} + +late_initcall_sync(initialize_hashrnd); |