Commit 96c36023 authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
Browse files

[NETLINK]: cb_lock does not needs ref count on sk



Here is a little optimisation for the cb_lock used by netlink_dump.
While fixing that race earlier, I noticed that the reference count
held by cb_lock is completely useless.  The reason is that in order
to obtain the protection of the reference count, you have to take
the cb_lock.  But the only way to take the cb_lock is through
dereferencing the socket.

That is, you must already possess a reference count on the socket
before you can take advantage of the reference count held by cb_lock.
As a corollary, we can remve the reference count held by the cb_lock.
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9dfa277f
...@@ -373,7 +373,6 @@ static int netlink_release(struct socket *sock) ...@@ -373,7 +373,6 @@ static int netlink_release(struct socket *sock)
nlk->cb->done(nlk->cb); nlk->cb->done(nlk->cb);
netlink_destroy_callback(nlk->cb); netlink_destroy_callback(nlk->cb);
nlk->cb = NULL; nlk->cb = NULL;
__sock_put(sk);
} }
spin_unlock(&nlk->cb_lock); spin_unlock(&nlk->cb_lock);
...@@ -1099,7 +1098,6 @@ static int netlink_dump(struct sock *sk) ...@@ -1099,7 +1098,6 @@ static int netlink_dump(struct sock *sk)
spin_unlock(&nlk->cb_lock); spin_unlock(&nlk->cb_lock);
netlink_destroy_callback(cb); netlink_destroy_callback(cb);
__sock_put(sk);
return 0; return 0;
} }
...@@ -1138,7 +1136,6 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, ...@@ -1138,7 +1136,6 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
return -EBUSY; return -EBUSY;
} }
nlk->cb = cb; nlk->cb = cb;
sock_hold(sk);
spin_unlock(&nlk->cb_lock); spin_unlock(&nlk->cb_lock);
netlink_dump(sk); netlink_dump(sk);
......
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