Commit 026659b9 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Ingo Molnar
Browse files

locking/local_lock: Add PREEMPT_RT support 



On PREEMPT_RT enabled kernels local_lock maps to a per CPU 'sleeping'
spinlock which protects the critical section while staying preemptible. CPU
locality is established by disabling migration.

Provide the necessary types and macros to substitute the non-RT variant.

Co-developed-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211306.023630962@linutronix.de
parent 31552385

include/linux/local_lock_internal.h

+44 −0
Original line number Diff line number Diff line
@@ -6,6 +6,8 @@ 
#include <linux/percpu-defs.h>

#include <linux/lockdep.h>



#ifndef CONFIG_PREEMPT_RT



typedef struct {

#ifdef CONFIG_DEBUG_LOCK_ALLOC

	struct lockdep_map	dep_map;
@@ -95,3 +97,45 @@ do { \ 
		local_lock_release(this_cpu_ptr(lock));		\

		local_irq_restore(flags);			\

	} while (0)



#else /* !CONFIG_PREEMPT_RT */



/*

 * On PREEMPT_RT local_lock maps to a per CPU spinlock, which protects the

 * critical section while staying preemptible.

 */

typedef spinlock_t local_lock_t;



#define INIT_LOCAL_LOCK(lockname) __LOCAL_SPIN_LOCK_UNLOCKED((lockname))



#define __local_lock_init(l)					\

	do {							\

		local_spin_lock_init((l));			\

	} while (0)



#define __local_lock(__lock)					\

	do {							\

		migrate_disable();				\

		spin_lock(this_cpu_ptr((__lock)));		\

	} while (0)



#define __local_lock_irq(lock)			__local_lock(lock)



#define __local_lock_irqsave(lock, flags)			\

	do {							\

		typecheck(unsigned long, flags);		\

		flags = 0;					\

		__local_lock(lock);				\

	} while (0)



#define __local_unlock(__lock)					\

	do {							\

		spin_unlock(this_cpu_ptr((__lock)));		\

		migrate_enable();				\

	} while (0)



#define __local_unlock_irq(lock)		__local_unlock(lock)



#define __local_unlock_irqrestore(lock, flags)	__local_unlock(lock)



#endif /* CONFIG_PREEMPT_RT */