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authorHannes Frederic Sowa <hannes@stressinduktion.org>2013-10-23 20:06:00 +0200
committerDavid S. Miller <davem@davemloft.net>2013-10-25 19:03:39 -0400
commit66415cf8a1b99d101317f5aa08574b1ec8832672 (patch)
treeb67df35008f4bcec22b5f1730acaf16bae63c262 /net/core
parentf84be2bd96a108b09c8440263fa3adb3fb225fa3 (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>
Diffstat (limited to 'net/core')
-rw-r--r--net/core/flow_dissector.c34
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);