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authorPaolo Bonzini <pbonzini@redhat.com>2017-08-01 17:24:05 +0200
committerIngo Molnar <mingo@kernel.org>2017-08-10 12:28:56 +0200
commit7a34bcb8b272b1300f0125c93a54f0c98812acdd (patch)
tree0b83ca55e6f18f63b995a4b1af68d800823f4204
parentjump_label: Fix concurrent static_key_enable/disable() (diff)
downloadlinux-7a34bcb8b272b1300f0125c93a54f0c98812acdd.tar.xz
linux-7a34bcb8b272b1300f0125c93a54f0c98812acdd.zip
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: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Peter 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: Ingo Molnar <mingo@kernel.org>
-rw-r--r--Documentation/static-keys.txt5
-rw-r--r--net/ipv4/udp.c3
-rw-r--r--net/ipv6/udp.c3
3 files changed, 7 insertions, 4 deletions
diff --git a/Documentation/static-keys.txt b/Documentation/static-keys.txt
index b83dfa1c0602..870b4be3cb11 100644
--- a/Documentation/static-keys.txt
+++ b/Documentation/static-keys.txt
@@ -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);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index e6276fa3750b..3037339ed8b8 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -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);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 578142b7ca3e..96d240798c38 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -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);