diff options
| -rw-r--r-- | include/net/sock.h | 1 | ||||
| -rw-r--r-- | net/core/sock.c | 37 |
2 files changed, 24 insertions, 14 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index 66a9a90f9558..c005c3c750e8 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1640,6 +1640,7 @@ static inline void unlock_sock_fast(struct sock *sk, bool slow) release_sock(sk); __release(&sk->sk_lock.slock); } else { + mutex_release(&sk->sk_lock.dep_map, _RET_IP_); spin_unlock_bh(&sk->sk_lock.slock); } } diff --git a/net/core/sock.c b/net/core/sock.c index 62627e868e03..512e629f9780 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -3179,17 +3179,15 @@ EXPORT_SYMBOL(sock_init_data); void lock_sock_nested(struct sock *sk, int subclass) { + /* The sk_lock has mutex_lock() semantics here. */ + mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_); + might_sleep(); spin_lock_bh(&sk->sk_lock.slock); if (sk->sk_lock.owned) __lock_sock(sk); sk->sk_lock.owned = 1; - spin_unlock(&sk->sk_lock.slock); - /* - * The sk_lock has mutex_lock() semantics here: - */ - mutex_acquire(&sk->sk_lock.dep_map, subclass, 0, _RET_IP_); - local_bh_enable(); + spin_unlock_bh(&sk->sk_lock.slock); } EXPORT_SYMBOL(lock_sock_nested); @@ -3227,24 +3225,35 @@ EXPORT_SYMBOL(release_sock); */ bool lock_sock_fast(struct sock *sk) __acquires(&sk->sk_lock.slock) { + /* The sk_lock has mutex_lock() semantics here. */ + mutex_acquire(&sk->sk_lock.dep_map, 0, 0, _RET_IP_); + might_sleep(); spin_lock_bh(&sk->sk_lock.slock); - if (!sk->sk_lock.owned) + if (!sk->sk_lock.owned) { /* - * Note : We must disable BH + * Fast path return with bottom halves disabled and + * sock::sk_lock.slock held. + * + * The 'mutex' is not contended and holding + * sock::sk_lock.slock prevents all other lockers to + * proceed so the corresponding unlock_sock_fast() can + * avoid the slow path of release_sock() completely and + * just release slock. + * + * From a semantical POV this is equivalent to 'acquiring' + * the 'mutex', hence the corresponding lockdep + * mutex_release() has to happen in the fast path of + * unlock_sock_fast(). */ return false; + } __lock_sock(sk); sk->sk_lock.owned = 1; - 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_); __acquire(&sk->sk_lock.slock); - local_bh_enable(); + spin_unlock_bh(&sk->sk_lock.slock); return true; } EXPORT_SYMBOL(lock_sock_fast); |