Commit 7a34bcb8 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Ingo Molnar
Browse files

jump_label: Do not use unserialized static_key_enabled() 



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.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1501601046-35683-3-git-send-email-pbonzini@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 1dbb6704

Documentation/static-keys.txt

+5 −0
Original line number Diff line number Diff line
@@ -149,6 +149,11 @@ 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);

net/ipv4/udp.c

+1 −2
Original line number Diff line number Diff line
@@ -1809,8 +1809,7 @@ 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);

}

EXPORT_SYMBOL(udp_encap_enable);

net/ipv6/udp.c

+1 −2
Original line number Diff line number Diff line
@@ -574,8 +574,7 @@ static __inline__ void udpv6_err(struct sk_buff *skb, 
static struct static_key udpv6_encap_needed __read_mostly;

void udpv6_encap_enable(void)

{

	if (!static_key_enabled(&udpv6_encap_needed))

		static_key_slow_inc(&udpv6_encap_needed);

	static_key_enable(&udpv6_encap_needed);

}

EXPORT_SYMBOL(udpv6_encap_enable);

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