Messages in this thread | | | Subject | Re: [PATCH 2/3] jump_labels: do not use unserialized static_key_enabled | From | Eric Dumazet <> | Date | Tue, 01 Aug 2017 13:52:14 -0700 |
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On Tue, 2017-08-01 at 17:24 +0200, Paolo Bonzini wrote: > Any use of key->enabled (that is static_key_enabled and static_key_count) > outside jump_label_lock should handle its own serialization. The only > two that are not doing so are the UDP encapsulation static keys. Change > them to use static_key_enable, which now correctly tests key->enabled under > the jump label lock. > > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Eric Dumazet <eric.dumazet@gmail.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > Documentation/static-keys.txt | 5 +++++ > net/ipv4/udp.c | 3 +-- > net/ipv6/udp.c | 3 +-- > 3 files changed, 7 insertions(+), 4 deletions(-) > > diff --git a/Documentation/static-keys.txt b/Documentation/static-keys.txt > index ef419fd0897f..181998852961 100644 > --- a/Documentation/static-keys.txt > +++ b/Documentation/static-keys.txt > @@ -142,6 +142,11 @@ static_branch_inc(), will change the branch back to true. Likewise, if the > key is initialized false, a 'static_branch_inc()', will change the branch to > true. And then a 'static_branch_dec()', will again make the branch false. > > +The state and the reference count can be retrieved with 'static_key_enabled()' > +and 'static_key_count()'. In general, if you use these functions, they > +should be protected with the same mutex used around the enable/disable > +or increment/decrement function. > + > Where an array of keys is required, it can be defined as: > > DEFINE_STATIC_KEY_ARRAY_TRUE(keys, count); > diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c > index 1d6219bf2d6b..74b7810df9fc 100644 > --- a/net/ipv4/udp.c > +++ b/net/ipv4/udp.c > @@ -1644,8 +1644,7 @@ static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb) > static struct static_key udp_encap_needed __read_mostly; > void udp_encap_enable(void) > { > - if (!static_key_enabled(&udp_encap_needed)) > - static_key_slow_inc(&udp_encap_needed); > + static_key_enable(&udp_encap_needed); > }
Looks good to me, but static_key_enable() is not serialized either ?
I suspect you should have CCed me on patch 1/3 :)
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