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authorIngo Molnar <mingo@elte.hu>2006-07-03 00:25:35 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-07-03 15:27:10 -0700
commita5b5bb9a053a973c23b867738c074acb3e80c0a0 (patch)
tree8eb78d458cfb309c566d6aaafb25639723920bcd /net/core/sock.c
parent0afffc723c8041a005134099847ac2a2fd0316a0 (diff)
downloadlwn-a5b5bb9a053a973c23b867738c074acb3e80c0a0.tar.gz
lwn-a5b5bb9a053a973c23b867738c074acb3e80c0a0.zip
[PATCH] lockdep: annotate sk_locks
Teach sk_lock semantics to the lock validator. In the softirq path the slock has mutex_trylock()+mutex_unlock() semantics, in the process context sock_lock() case it has mutex_lock()/mutex_unlock() semantics. Thus we treat sock_owned_by_user() flagged areas as an exclusion area too, not just those areas covered by a held sk_lock.slock. Effect on non-lockdep kernels: minimal, sk_lock_sock_init() has been turned into an inline function. Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'net/core/sock.c')
-rw-r--r--net/core/sock.c97
1 files changed, 88 insertions, 9 deletions
diff --git a/net/core/sock.c b/net/core/sock.c
index 0b4d5d25b23c..51fcfbc041a7 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -133,7 +133,42 @@
* Each address family might have different locking rules, so we have
* one slock key per address family:
*/
-struct lock_class_key af_family_keys[AF_MAX];
+static struct lock_class_key af_family_keys[AF_MAX];
+static struct lock_class_key af_family_slock_keys[AF_MAX];
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+/*
+ * Make lock validator output more readable. (we pre-construct these
+ * strings build-time, so that runtime initialization of socket
+ * locks is fast):
+ */
+static const char *af_family_key_strings[AF_MAX+1] = {
+ "sk_lock-AF_UNSPEC", "sk_lock-AF_UNIX" , "sk_lock-AF_INET" ,
+ "sk_lock-AF_AX25" , "sk_lock-AF_IPX" , "sk_lock-AF_APPLETALK",
+ "sk_lock-AF_NETROM", "sk_lock-AF_BRIDGE" , "sk_lock-AF_ATMPVC" ,
+ "sk_lock-AF_X25" , "sk_lock-AF_INET6" , "sk_lock-AF_ROSE" ,
+ "sk_lock-AF_DECnet", "sk_lock-AF_NETBEUI" , "sk_lock-AF_SECURITY" ,
+ "sk_lock-AF_KEY" , "sk_lock-AF_NETLINK" , "sk_lock-AF_PACKET" ,
+ "sk_lock-AF_ASH" , "sk_lock-AF_ECONET" , "sk_lock-AF_ATMSVC" ,
+ "sk_lock-21" , "sk_lock-AF_SNA" , "sk_lock-AF_IRDA" ,
+ "sk_lock-AF_PPPOX" , "sk_lock-AF_WANPIPE" , "sk_lock-AF_LLC" ,
+ "sk_lock-27" , "sk_lock-28" , "sk_lock-29" ,
+ "sk_lock-AF_TIPC" , "sk_lock-AF_BLUETOOTH", "sk_lock-AF_MAX"
+};
+static const char *af_family_slock_key_strings[AF_MAX+1] = {
+ "slock-AF_UNSPEC", "slock-AF_UNIX" , "slock-AF_INET" ,
+ "slock-AF_AX25" , "slock-AF_IPX" , "slock-AF_APPLETALK",
+ "slock-AF_NETROM", "slock-AF_BRIDGE" , "slock-AF_ATMPVC" ,
+ "slock-AF_X25" , "slock-AF_INET6" , "slock-AF_ROSE" ,
+ "slock-AF_DECnet", "slock-AF_NETBEUI" , "slock-AF_SECURITY" ,
+ "slock-AF_KEY" , "slock-AF_NETLINK" , "slock-AF_PACKET" ,
+ "slock-AF_ASH" , "slock-AF_ECONET" , "slock-AF_ATMSVC" ,
+ "slock-21" , "slock-AF_SNA" , "slock-AF_IRDA" ,
+ "slock-AF_PPPOX" , "slock-AF_WANPIPE" , "slock-AF_LLC" ,
+ "slock-27" , "slock-28" , "slock-29" ,
+ "slock-AF_TIPC" , "slock-AF_BLUETOOTH", "slock-AF_MAX"
+};
+#endif
/*
* sk_callback_lock locking rules are per-address-family,
@@ -249,9 +284,16 @@ int sk_receive_skb(struct sock *sk, struct sk_buff *skb)
skb->dev = NULL;
bh_lock_sock(sk);
- if (!sock_owned_by_user(sk))
+ if (!sock_owned_by_user(sk)) {
+ /*
+ * trylock + unlock semantics:
+ */
+ mutex_acquire(&sk->sk_lock.dep_map, 0, 1, _RET_IP_);
+
rc = sk->sk_backlog_rcv(sk, skb);
- else
+
+ mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
+ } else
sk_add_backlog(sk, skb);
bh_unlock_sock(sk);
out:
@@ -761,6 +803,33 @@ lenout:
return 0;
}
+/*
+ * Initialize an sk_lock.
+ *
+ * (We also register the sk_lock with the lock validator.)
+ */
+static void inline sock_lock_init(struct sock *sk)
+{
+ spin_lock_init(&sk->sk_lock.slock);
+ sk->sk_lock.owner = NULL;
+ init_waitqueue_head(&sk->sk_lock.wq);
+ /*
+ * Make sure we are not reinitializing a held lock:
+ */
+ debug_check_no_locks_freed((void *)&sk->sk_lock, sizeof(sk->sk_lock));
+
+ /*
+ * Mark both the sk_lock and the sk_lock.slock as a
+ * per-address-family lock class:
+ */
+ lockdep_set_class_and_name(&sk->sk_lock.slock,
+ af_family_slock_keys + sk->sk_family,
+ af_family_slock_key_strings[sk->sk_family]);
+ lockdep_init_map(&sk->sk_lock.dep_map,
+ af_family_key_strings[sk->sk_family],
+ af_family_keys + sk->sk_family);
+}
+
/**
* sk_alloc - All socket objects are allocated here
* @family: protocol family
@@ -1465,24 +1534,34 @@ void sock_init_data(struct socket *sock, struct sock *sk)
void fastcall lock_sock(struct sock *sk)
{
might_sleep();
- spin_lock_bh(&(sk->sk_lock.slock));
+ spin_lock_bh(&sk->sk_lock.slock);
if (sk->sk_lock.owner)
__lock_sock(sk);
sk->sk_lock.owner = (void *)1;
- spin_unlock_bh(&(sk->sk_lock.slock));
+ spin_unlock(&sk->sk_lock.slock);
+ /*
+ * The sk_lock has mutex_lock() semantics here:
+ */
+ mutex_acquire(&sk->sk_lock.dep_map, 0, 0, _RET_IP_);
+ local_bh_enable();
}
EXPORT_SYMBOL(lock_sock);
void fastcall release_sock(struct sock *sk)
{
- spin_lock_bh(&(sk->sk_lock.slock));
+ /*
+ * The sk_lock has mutex_unlock() semantics:
+ */
+ mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
+
+ spin_lock_bh(&sk->sk_lock.slock);
if (sk->sk_backlog.tail)
__release_sock(sk);
sk->sk_lock.owner = NULL;
- if (waitqueue_active(&(sk->sk_lock.wq)))
- wake_up(&(sk->sk_lock.wq));
- spin_unlock_bh(&(sk->sk_lock.slock));
+ if (waitqueue_active(&sk->sk_lock.wq))
+ wake_up(&sk->sk_lock.wq);
+ spin_unlock_bh(&sk->sk_lock.slock);
}
EXPORT_SYMBOL(release_sock);