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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2009-07-15 23:13:10 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-07-16 18:05:26 -0700 |
| commit | 4dc6dc7162c08b9965163c9ab3f9375d4adff2c7 (patch) | |
| tree | f4b9959e9ca5e5b8bdb6301663a15e0f67d4c68c /include | |
| parent | 303d67c288319768b19ed8dbed429fef7eb7c275 (diff) | |
| download | linux-4dc6dc7162c08b9965163c9ab3f9375d4adff2c7.tar.bz2 | |
net: sock_copy() fixes
Commit e912b1142be8f1e2c71c71001dc992c6e5eb2ec1
(net: sk_prot_alloc() should not blindly overwrite memory)
took care of not zeroing whole new socket at allocation time.
sock_copy() is another spot where we should be very careful.
We should not set refcnt to a non null value, until
we are sure other fields are correctly setup, or
a lockless reader could catch this socket by mistake,
while not fully (re)initialized.
This patch puts sk_node & sk_refcnt to the very beginning
of struct sock to ease sock_copy() & sk_prot_alloc() job.
We add appropriate smp_wmb() before sk_refcnt initializations
to match our RCU requirements (changes to sock keys should
be committed to memory before sk_refcnt setting)
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/sock.h | 32 |
1 files changed, 19 insertions, 13 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index 2c0da9239b95..950409dcec3d 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -104,15 +104,15 @@ struct net; /** * struct sock_common - minimal network layer representation of sockets + * @skc_node: main hash linkage for various protocol lookup tables + * @skc_nulls_node: main hash linkage for UDP/UDP-Lite protocol + * @skc_refcnt: reference count + * @skc_hash: hash value used with various protocol lookup tables * @skc_family: network address family * @skc_state: Connection state * @skc_reuse: %SO_REUSEADDR setting * @skc_bound_dev_if: bound device index if != 0 - * @skc_node: main hash linkage for various protocol lookup tables - * @skc_nulls_node: main hash linkage for UDP/UDP-Lite protocol * @skc_bind_node: bind hash linkage for various protocol lookup tables - * @skc_refcnt: reference count - * @skc_hash: hash value used with various protocol lookup tables * @skc_prot: protocol handlers inside a network family * @skc_net: reference to the network namespace of this socket * @@ -120,17 +120,21 @@ struct net; * for struct sock and struct inet_timewait_sock. */ struct sock_common { - unsigned short skc_family; - volatile unsigned char skc_state; - unsigned char skc_reuse; - int skc_bound_dev_if; + /* + * first fields are not copied in sock_copy() + */ union { struct hlist_node skc_node; struct hlist_nulls_node skc_nulls_node; }; - struct hlist_node skc_bind_node; atomic_t skc_refcnt; + unsigned int skc_hash; + unsigned short skc_family; + volatile unsigned char skc_state; + unsigned char skc_reuse; + int skc_bound_dev_if; + struct hlist_node skc_bind_node; struct proto *skc_prot; #ifdef CONFIG_NET_NS struct net *skc_net; @@ -208,15 +212,17 @@ struct sock { * don't add nothing before this first member (__sk_common) --acme */ struct sock_common __sk_common; +#define sk_node __sk_common.skc_node +#define sk_nulls_node __sk_common.skc_nulls_node +#define sk_refcnt __sk_common.skc_refcnt + +#define sk_copy_start __sk_common.skc_hash +#define sk_hash __sk_common.skc_hash #define sk_family __sk_common.skc_family #define sk_state __sk_common.skc_state #define sk_reuse __sk_common.skc_reuse #define sk_bound_dev_if __sk_common.skc_bound_dev_if -#define sk_node __sk_common.skc_node -#define sk_nulls_node __sk_common.skc_nulls_node #define sk_bind_node __sk_common.skc_bind_node -#define sk_refcnt __sk_common.skc_refcnt -#define sk_hash __sk_common.skc_hash #define sk_prot __sk_common.skc_prot #define sk_net __sk_common.skc_net kmemcheck_bitfield_begin(flags); |