diff options
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/datagram.c | 6 | ||||
| -rw-r--r-- | net/core/sock.c | 33 |
2 files changed, 37 insertions, 2 deletions
diff --git a/net/core/datagram.c b/net/core/datagram.c index e0097531417..f5b6f43a4c2 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -229,15 +229,17 @@ EXPORT_SYMBOL(skb_free_datagram); void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb) { + bool slow; + if (likely(atomic_read(&skb->users) == 1)) smp_rmb(); else if (likely(!atomic_dec_and_test(&skb->users))) return; - lock_sock_bh(sk); + slow = lock_sock_fast(sk); skb_orphan(skb); sk_mem_reclaim_partial(sk); - unlock_sock_bh(sk); + unlock_sock_fast(sk, slow); /* skb is now orphaned, can be freed outside of locked section */ __kfree_skb(skb); diff --git a/net/core/sock.c b/net/core/sock.c index 37fe9b6adad..2cf7f9f7e77 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2007,6 +2007,39 @@ void release_sock(struct sock *sk) } EXPORT_SYMBOL(release_sock); +/** + * lock_sock_fast - fast version of lock_sock + * @sk: socket + * + * This version should be used for very small section, where process wont block + * return false if fast path is taken + * sk_lock.slock locked, owned = 0, BH disabled + * return true if slow path is taken + * sk_lock.slock unlocked, owned = 1, BH enabled + */ +bool lock_sock_fast(struct sock *sk) +{ + might_sleep(); + spin_lock_bh(&sk->sk_lock.slock); + + if (!sk->sk_lock.owned) + /* + * Note : We must disable BH + */ + 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_); + local_bh_enable(); + return true; +} +EXPORT_SYMBOL(lock_sock_fast); + int sock_get_timestamp(struct sock *sk, struct timeval __user *userstamp) { struct timeval tv; |