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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-09-08 21:31:35 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-09-08 21:31:35 -0700 |
| commit | e0386005ff2a729998735e10769d99e1acbc2dd1 (patch) | |
| tree | c04134571b728581d9692fb16dffcdd38d52dbda /net/ipv4/protocol.c | |
| parent | 92e32eaee288ee2e838fe76680cbaeaea25643c6 (diff) | |
| download | linux-e0386005ff2a729998735e10769d99e1acbc2dd1.tar.bz2 | |
net: inet_add_protocol() can use cmpxchg()
Use cmpxchg() to get rid of spinlocks in inet_add_protocol() and
friends.
inet_protos[] & inet6_protos[] are moved to read_mostly section
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/protocol.c')
| -rw-r--r-- | net/ipv4/protocol.c | 31 |
1 files changed, 5 insertions, 26 deletions
diff --git a/net/ipv4/protocol.c b/net/ipv4/protocol.c index f2d297351405..65699c24411c 100644 --- a/net/ipv4/protocol.c +++ b/net/ipv4/protocol.c @@ -28,8 +28,7 @@ #include <linux/spinlock.h> #include <net/protocol.h> -const struct net_protocol *inet_protos[MAX_INET_PROTOS] ____cacheline_aligned_in_smp; -static DEFINE_SPINLOCK(inet_proto_lock); +const struct net_protocol *inet_protos[MAX_INET_PROTOS] __read_mostly; /* * Add a protocol handler to the hash tables @@ -37,20 +36,9 @@ static DEFINE_SPINLOCK(inet_proto_lock); int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol) { - int hash, ret; + int hash = protocol & (MAX_INET_PROTOS - 1); - hash = protocol & (MAX_INET_PROTOS - 1); - - spin_lock_bh(&inet_proto_lock); - if (inet_protos[hash]) { - ret = -1; - } else { - inet_protos[hash] = prot; - ret = 0; - } - spin_unlock_bh(&inet_proto_lock); - - return ret; + return !cmpxchg(&inet_protos[hash], NULL, prot) ? 0 : -1; } EXPORT_SYMBOL(inet_add_protocol); @@ -60,18 +48,9 @@ EXPORT_SYMBOL(inet_add_protocol); int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol) { - int hash, ret; - - hash = protocol & (MAX_INET_PROTOS - 1); + int ret, hash = protocol & (MAX_INET_PROTOS - 1); - spin_lock_bh(&inet_proto_lock); - if (inet_protos[hash] == prot) { - inet_protos[hash] = NULL; - ret = 0; - } else { - ret = -1; - } - spin_unlock_bh(&inet_proto_lock); + ret = (cmpxchg(&inet_protos[hash], prot, NULL) == prot) ? 0 : -1; synchronize_net(); |