diff options
Diffstat (limited to 'net/core/filter.c')
-rw-r--r-- | net/core/filter.c | 58 |
1 files changed, 46 insertions, 12 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index bd903aaf7aa..1f0068eae50 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -387,6 +387,25 @@ int sk_chk_filter(struct sock_filter *filter, int flen) } /** + * sk_filter_rcu_release: Release a socket filter by rcu_head + * @rcu: rcu_head that contains the sk_filter to free + */ +static void sk_filter_rcu_release(struct rcu_head *rcu) +{ + struct sk_filter *fp = container_of(rcu, struct sk_filter, rcu); + + sk_filter_release(fp); +} + +static void sk_filter_delayed_uncharge(struct sock *sk, struct sk_filter *fp) +{ + unsigned int size = sk_filter_len(fp); + + atomic_sub(size, &sk->sk_omem_alloc); + call_rcu_bh(&fp->rcu, sk_filter_rcu_release); +} + +/** * sk_attach_filter - attach a socket filter * @fprog: the filter program * @sk: the socket to use @@ -398,7 +417,7 @@ int sk_chk_filter(struct sock_filter *filter, int flen) */ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) { - struct sk_filter *fp; + struct sk_filter *fp, *old_fp; unsigned int fsize = sizeof(struct sock_filter) * fprog->len; int err; @@ -418,19 +437,34 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) fp->len = fprog->len; err = sk_chk_filter(fp->insns, fp->len); - if (!err) { - struct sk_filter *old_fp; - - rcu_read_lock_bh(); - old_fp = rcu_dereference(sk->sk_filter); - rcu_assign_pointer(sk->sk_filter, fp); - rcu_read_unlock_bh(); - fp = old_fp; + if (err) { + sk_filter_uncharge(sk, fp); + return err; } - if (fp) - sk_filter_release(sk, fp); - return err; + rcu_read_lock_bh(); + old_fp = rcu_dereference(sk->sk_filter); + rcu_assign_pointer(sk->sk_filter, fp); + rcu_read_unlock_bh(); + + sk_filter_delayed_uncharge(sk, old_fp); + return 0; +} + +int sk_detach_filter(struct sock *sk) +{ + int ret = -ENOENT; + struct sk_filter *filter; + + rcu_read_lock_bh(); + filter = rcu_dereference(sk->sk_filter); + if (filter) { + rcu_assign_pointer(sk->sk_filter, NULL); + sk_filter_delayed_uncharge(sk, filter); + ret = 0; + } + rcu_read_unlock_bh(); + return ret; } EXPORT_SYMBOL(sk_chk_filter); |