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net: sk_{detach|attach}_filter() rcu fixes

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sk_attach_filter() and sk_detach_filter() are run with socket locked.

Use the appropriate rcu_dereference_protected() instead of blocking BH,
and rcu_dereference_bh().
There is no point adding BH prevention and memory barrier.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2010-09-27 06:07:30 +00:00 committed by David S. Miller
parent 7fa7cb7109
commit f91ff5b9ff
1 changed files with 4 additions and 6 deletions
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10
net/core/filter.c
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@ -638,10 +638,9 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)
return err;
}
rcu_read_lock_bh();
old_fp = rcu_dereference_bh(sk->sk_filter);
old_fp = rcu_dereference_protected(sk->sk_filter,
sock_owned_by_user(sk));
rcu_assign_pointer(sk->sk_filter, fp);
rcu_read_unlock_bh();
if (old_fp)
sk_filter_delayed_uncharge(sk, old_fp);
@ -654,14 +653,13 @@ int sk_detach_filter(struct sock *sk)
int ret = -ENOENT;
struct sk_filter *filter;
rcu_read_lock_bh();
filter = rcu_dereference_bh(sk->sk_filter);
filter = rcu_dereference_protected(sk->sk_filter,
sock_owned_by_user(sk));
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_GPL(sk_detach_filter);