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authorEric Dumazet <dada1@cosmosbay.com>2008-11-24 04:22:55 +0300
committerDavid S. Miller <davem@davemloft.net>2008-11-24 04:22:55 +0300
commitc25eb3bfb97294d0543a81230fbc237046b4b84c (patch)
tree6c9deabfb12f4d31f280cfcfe7e7580a2089931c /include/net
parent8c862c23e2563e6aedfc6c4aa6827cadb83f2414 (diff)
downloadlinux-c25eb3bfb97294d0543a81230fbc237046b4b84c.tar.xz
net: Convert TCP/DCCP listening hash tables to use RCU
This is the last step to be able to perform full RCU lookups in __inet_lookup() : After established/timewait tables, we add RCU lookups to listening hash table. The only trick here is that a socket of a given type (TCP ipv4, TCP ipv6, ...) can now flight between two different tables (established and listening) during a RCU grace period, so we must use different 'nulls' end-of-chain values for two tables. We define a large value : #define LISTENING_NULLS_BASE (1U << 29) So that slots in listening table are guaranteed to have different end-of-chain values than slots in established table. A reader can still detect it finished its lookup in the right chain. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net')
-rw-r--r--include/net/inet_hashtables.h9
1 files changed, 8 insertions, 1 deletions
diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index ec7ee2e46d8c..f44bb5c77a70 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -99,9 +99,16 @@ struct inet_bind_hashbucket {
struct hlist_head chain;
};
+/*
+ * Sockets can be hashed in established or listening table
+ * We must use different 'nulls' end-of-chain value for listening
+ * hash table, or we might find a socket that was closed and
+ * reallocated/inserted into established hash table
+ */
+#define LISTENING_NULLS_BASE (1U << 29)
struct inet_listen_hashbucket {
spinlock_t lock;
- struct hlist_head head;
+ struct hlist_nulls_head head;
};
/* This is for listening sockets, thus all sockets which possess wildcards. */