diff options
author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-09-09 00:31:35 -0400 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2010-09-09 00:31:35 -0400 |
commit | e0386005ff2a729998735e10769d99e1acbc2dd1 (patch) | |
tree | c04134571b728581d9692fb16dffcdd38d52dbda | |
parent | 92e32eaee288ee2e838fe76680cbaeaea25643c6 (diff) |
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>
-rw-r--r-- | net/ipv4/protocol.c | 31 | ||||
-rw-r--r-- | net/ipv6/protocol.c | 32 |
2 files changed, 9 insertions, 54 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 @@ | |||
28 | #include <linux/spinlock.h> | 28 | #include <linux/spinlock.h> |
29 | #include <net/protocol.h> | 29 | #include <net/protocol.h> |
30 | 30 | ||
31 | const struct net_protocol *inet_protos[MAX_INET_PROTOS] ____cacheline_aligned_in_smp; | 31 | const struct net_protocol *inet_protos[MAX_INET_PROTOS] __read_mostly; |
32 | static DEFINE_SPINLOCK(inet_proto_lock); | ||
33 | 32 | ||
34 | /* | 33 | /* |
35 | * Add a protocol handler to the hash tables | 34 | * Add a protocol handler to the hash tables |
@@ -37,20 +36,9 @@ static DEFINE_SPINLOCK(inet_proto_lock); | |||
37 | 36 | ||
38 | int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol) | 37 | int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol) |
39 | { | 38 | { |
40 | int hash, ret; | 39 | int hash = protocol & (MAX_INET_PROTOS - 1); |
41 | 40 | ||
42 | hash = protocol & (MAX_INET_PROTOS - 1); | 41 | return !cmpxchg(&inet_protos[hash], NULL, prot) ? 0 : -1; |
43 | |||
44 | spin_lock_bh(&inet_proto_lock); | ||
45 | if (inet_protos[hash]) { | ||
46 | ret = -1; | ||
47 | } else { | ||
48 | inet_protos[hash] = prot; | ||
49 | ret = 0; | ||
50 | } | ||
51 | spin_unlock_bh(&inet_proto_lock); | ||
52 | |||
53 | return ret; | ||
54 | } | 42 | } |
55 | EXPORT_SYMBOL(inet_add_protocol); | 43 | EXPORT_SYMBOL(inet_add_protocol); |
56 | 44 | ||
@@ -60,18 +48,9 @@ EXPORT_SYMBOL(inet_add_protocol); | |||
60 | 48 | ||
61 | int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol) | 49 | int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol) |
62 | { | 50 | { |
63 | int hash, ret; | 51 | int ret, hash = protocol & (MAX_INET_PROTOS - 1); |
64 | |||
65 | hash = protocol & (MAX_INET_PROTOS - 1); | ||
66 | 52 | ||
67 | spin_lock_bh(&inet_proto_lock); | 53 | ret = (cmpxchg(&inet_protos[hash], prot, NULL) == prot) ? 0 : -1; |
68 | if (inet_protos[hash] == prot) { | ||
69 | inet_protos[hash] = NULL; | ||
70 | ret = 0; | ||
71 | } else { | ||
72 | ret = -1; | ||
73 | } | ||
74 | spin_unlock_bh(&inet_proto_lock); | ||
75 | 54 | ||
76 | synchronize_net(); | 55 | synchronize_net(); |
77 | 56 | ||
diff --git a/net/ipv6/protocol.c b/net/ipv6/protocol.c index 1fa3468f0f32..9bb936ae2452 100644 --- a/net/ipv6/protocol.c +++ b/net/ipv6/protocol.c | |||
@@ -25,28 +25,14 @@ | |||
25 | #include <linux/spinlock.h> | 25 | #include <linux/spinlock.h> |
26 | #include <net/protocol.h> | 26 | #include <net/protocol.h> |
27 | 27 | ||
28 | const struct inet6_protocol *inet6_protos[MAX_INET_PROTOS]; | 28 | const struct inet6_protocol *inet6_protos[MAX_INET_PROTOS] __read_mostly; |
29 | static DEFINE_SPINLOCK(inet6_proto_lock); | ||
30 | |||
31 | 29 | ||
32 | int inet6_add_protocol(const struct inet6_protocol *prot, unsigned char protocol) | 30 | int inet6_add_protocol(const struct inet6_protocol *prot, unsigned char protocol) |
33 | { | 31 | { |
34 | int ret, hash = protocol & (MAX_INET_PROTOS - 1); | 32 | int hash = protocol & (MAX_INET_PROTOS - 1); |
35 | |||
36 | spin_lock_bh(&inet6_proto_lock); | ||
37 | |||
38 | if (inet6_protos[hash]) { | ||
39 | ret = -1; | ||
40 | } else { | ||
41 | inet6_protos[hash] = prot; | ||
42 | ret = 0; | ||
43 | } | ||
44 | |||
45 | spin_unlock_bh(&inet6_proto_lock); | ||
46 | 33 | ||
47 | return ret; | 34 | return !cmpxchg(&inet6_protos[hash], NULL, prot) ? 0 : -1; |
48 | } | 35 | } |
49 | |||
50 | EXPORT_SYMBOL(inet6_add_protocol); | 36 | EXPORT_SYMBOL(inet6_add_protocol); |
51 | 37 | ||
52 | /* | 38 | /* |
@@ -57,20 +43,10 @@ int inet6_del_protocol(const struct inet6_protocol *prot, unsigned char protocol | |||
57 | { | 43 | { |
58 | int ret, hash = protocol & (MAX_INET_PROTOS - 1); | 44 | int ret, hash = protocol & (MAX_INET_PROTOS - 1); |
59 | 45 | ||
60 | spin_lock_bh(&inet6_proto_lock); | 46 | ret = (cmpxchg(&inet6_protos[hash], prot, NULL) == prot) ? 0 : -1; |
61 | |||
62 | if (inet6_protos[hash] != prot) { | ||
63 | ret = -1; | ||
64 | } else { | ||
65 | inet6_protos[hash] = NULL; | ||
66 | ret = 0; | ||
67 | } | ||
68 | |||
69 | spin_unlock_bh(&inet6_proto_lock); | ||
70 | 47 | ||
71 | synchronize_net(); | 48 | synchronize_net(); |
72 | 49 | ||
73 | return ret; | 50 | return ret; |
74 | } | 51 | } |
75 | |||
76 | EXPORT_SYMBOL(inet6_del_protocol); | 52 | EXPORT_SYMBOL(inet6_del_protocol); |