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Commit 8b7b4128 authored by Marc Zyngier's avatar Marc Zyngier Committed by Ingo Molnar
Browse files

jump_label: Split out code under the hotplug lock 



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: default avatarMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: default avatarPeter 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: default avatarIngo Molnar <mingo@kernel.org>
parent b70cecf4

kernel/jump_label.c

+19 −9
Original line number Diff line number Diff line
@@ -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();



	/*
@@ -100,11 +99,9 @@ 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();

	if (atomic_read(&key->enabled) == 0) {
@@ -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();

}