GitHub-Mirror/Star64_linux
2
0
Fork 0
mirror of https://github.com/Fishwaldo/Star64_linux.git synced 2025-06-27 09:02:06 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

net: Convert TCP/DCCP listening hash tables to use RCU

Browse source 
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>
This commit is contained in:
Eric Dumazet 2008-11-23 17:22:55 -08:00 • committed by David S. Miller
parent 8c862c23e2
commit c25eb3bfb9
5 changed files with 145 additions and 114 deletions
Download patch file Download diff file Expand all files Collapse all files

9
include/net/inet_hashtables.h
View file

@ -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. */