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jump_label: Split out code under the hotplug lock

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In order to later introduce an "already locked" version of some
of the static key funcions, let's split the code into the core stuff
(the *_cpuslocked functions) and the usual helpers, which now
take/release the hotplug lock and call into the _cpuslocked
versions.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20170801080257.5056-3-marc.zyngier@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Marc Zyngier 2017-08-01 09:02:55 +01:00 committed by Ingo Molnar
parent b70cecf4b6
commit 8b7b412807
1 changed files with 19 additions and 9 deletions
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28
kernel/jump_label.c
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@ -79,11 +79,10 @@ int static_key_count(struct static_key *key)
}
EXPORT_SYMBOL_GPL(static_key_count);
void static_key_slow_inc(struct static_key *key)
static void static_key_slow_inc_cpuslocked(struct static_key *key)
{
int v, v1;
cpus_read_lock();
STATIC_KEY_CHECK_USE();
/*
@ -100,10 +99,8 @@ void static_key_slow_inc(struct static_key *key)
*/
for (v = atomic_read(&key->enabled); v > 0; v = v1) {
v1 = atomic_cmpxchg(&key->enabled, v, v + 1);
if (likely(v1 == v)) {
cpus_read_unlock();
if (likely(v1 == v))
return;
}
}
jump_label_lock();
@ -119,6 +116,12 @@ void static_key_slow_inc(struct static_key *key)
atomic_inc(&key->enabled);
}
jump_label_unlock();
}
void static_key_slow_inc(struct static_key *key)
{
cpus_read_lock();
static_key_slow_inc_cpuslocked(key);
cpus_read_unlock();
}
EXPORT_SYMBOL_GPL(static_key_slow_inc);
@ -163,10 +166,10 @@ void static_key_disable(struct static_key *key)
}
EXPORT_SYMBOL_GPL(static_key_disable);
static void __static_key_slow_dec(struct static_key *key,
unsigned long rate_limit, struct delayed_work *work)
static void static_key_slow_dec_cpuslocked(struct static_key *key,
unsigned long rate_limit,
struct delayed_work *work)
{
cpus_read_lock();
/*
* The negative count check is valid even when a negative
* key->enabled is in use by static_key_slow_inc(); a
@ -177,7 +180,6 @@ static void __static_key_slow_dec(struct static_key *key,
if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) {
WARN(atomic_read(&key->enabled) < 0,
"jump label: negative count!\n");
cpus_read_unlock();
return;
}
@ -188,6 +190,14 @@ static void __static_key_slow_dec(struct static_key *key,
jump_label_update(key);
}
jump_label_unlock();
}
static void __static_key_slow_dec(struct static_key *key,
unsigned long rate_limit,
struct delayed_work *work)
{
cpus_read_lock();
static_key_slow_dec_cpuslocked(key, rate_limit, work);
cpus_read_unlock();
}