diff options
| author | Hannes Frederic Sowa <hannes@stressinduktion.org> | 2013-10-23 20:06:00 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-10-25 19:03:39 -0400 |
| commit | 66415cf8a1b99d101317f5aa08574b1ec8832672 (patch) | |
| tree | b67df35008f4bcec22b5f1730acaf16bae63c262 | |
| parent | f84be2bd96a108b09c8440263fa3adb3fb225fa3 (diff) | |
net: initialize hashrnd in flow_dissector with net_get_random_once
We also can defer the initialization of hashrnd in flow_dissector
to its first use. Since net_get_random_once is irq safe now we don't
have to audit the call paths if one of this functions get called by an
interrupt handler.
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/core/flow_dissector.c | 34 |
1 files changed, 21 insertions, 13 deletions
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index f8e25ac41c6c..5cac36e6ccd1 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -184,6 +184,22 @@ ipv6: EXPORT_SYMBOL(skb_flow_dissect); static u32 hashrnd __read_mostly; +static __always_inline void __flow_hash_secret_init(void) +{ + net_get_random_once(&hashrnd, sizeof(hashrnd)); +} + +static __always_inline u32 __flow_hash_3words(u32 a, u32 b, u32 c) +{ + __flow_hash_secret_init(); + return jhash_3words(a, b, c, hashrnd); +} + +static __always_inline u32 __flow_hash_1word(u32 a) +{ + __flow_hash_secret_init(); + return jhash_1word(a, hashrnd); +} /* * __skb_get_rxhash: calculate a flow hash based on src/dst addresses @@ -210,9 +226,9 @@ void __skb_get_rxhash(struct sk_buff *skb) swap(keys.port16[0], keys.port16[1]); } - hash = jhash_3words((__force u32)keys.dst, - (__force u32)keys.src, - (__force u32)keys.ports, hashrnd); + hash = __flow_hash_3words((__force u32)keys.dst, + (__force u32)keys.src, + (__force u32)keys.ports); if (!hash) hash = 1; @@ -248,7 +264,7 @@ u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb, hash = skb->sk->sk_hash; else hash = (__force u16) skb->protocol; - hash = jhash_1word(hash, hashrnd); + hash = __flow_hash_1word(hash); return (u16) (((u64) hash * qcount) >> 32) + qoffset; } @@ -340,7 +356,7 @@ static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb) else hash = (__force u16) skb->protocol ^ skb->rxhash; - hash = jhash_1word(hash, hashrnd); + hash = __flow_hash_1word(hash); queue_index = map->queues[ ((u64)hash * map->len) >> 32]; } @@ -395,11 +411,3 @@ struct netdev_queue *netdev_pick_tx(struct net_device *dev, 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); |