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locking/spinlock: Provide RT variant header: <linux/spinlock_rt.h>

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Provide the necessary wrappers around the actual rtmutex based spinlock
implementation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210815211303.712897671@linutronix.de
This commit is contained in:
Thomas Gleixner 2021-08-15 23:28:23 +02:00 • committed by Ingo Molnar
parent 051790eecc
commit 342a93247e
3 changed files with 162 additions and 1 deletions
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11
include/linux/spinlock.h
View file

@ -312,8 +312,10 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
1 : ({ local_irq_restore(flags); 0; }); \
})
/* Include rwlock functions */
#ifndef CONFIG_PREEMPT_RT
/* Include rwlock functions for !RT */
#include <linux/rwlock.h>
#endif
/*
* Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
@ -324,6 +326,9 @@ static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
# include <linux/spinlock_api_up.h>
#endif
/* Non PREEMPT_RT kernel, map to raw spinlocks: */
#ifndef CONFIG_PREEMPT_RT
/*
* Map the spin_lock functions to the raw variants for PREEMPT_RT=n
*/
@ -458,6 +463,10 @@ static __always_inline int spin_is_contended(spinlock_t *lock)
#define assert_spin_locked(lock) assert_raw_spin_locked(&(lock)->rlock)
#else /* !CONFIG_PREEMPT_RT */
# include <linux/spinlock_rt.h>
#endif /* CONFIG_PREEMPT_RT */
/*
* Pull the atomic_t declaration:
* (asm-mips/atomic.h needs above definitions)

3
include/linux/spinlock_api_smp.h
View file

@ -187,6 +187,9 @@ static inline int __raw_spin_trylock_bh(raw_spinlock_t *lock)
return 0;
}
/* PREEMPT_RT has its own rwlock implementation */
#ifndef CONFIG_PREEMPT_RT
#include <linux/rwlock_api_smp.h>
#endif
#endif /* __LINUX_SPINLOCK_API_SMP_H */

149
include/linux/spinlock_rt.h Normal file
View file

@ -0,0 +1,149 @@
// SPDX-License-Identifier: GPL-2.0-only
#ifndef __LINUX_SPINLOCK_RT_H
#define __LINUX_SPINLOCK_RT_H
#ifndef __LINUX_SPINLOCK_H
#error Do not include directly. Use spinlock.h
#endif
#ifdef CONFIG_DEBUG_LOCK_ALLOC
extern void __rt_spin_lock_init(spinlock_t *lock, const char *name,
struct lock_class_key *key);
#else
static inline void __rt_spin_lock_init(spinlock_t *lock, const char *name,
struct lock_class_key *key)
{
}
#endif
#define spin_lock_init(slock) \
do { \
static struct lock_class_key __key; \
\
rt_mutex_base_init(&(slock)->lock); \
__rt_spin_lock_init(slock, #slock, &__key); \
} while (0)
extern void rt_spin_lock(spinlock_t *lock);
extern void rt_spin_lock_nested(spinlock_t *lock, int subclass);
extern void rt_spin_lock_nest_lock(spinlock_t *lock, struct lockdep_map *nest_lock);
extern void rt_spin_unlock(spinlock_t *lock);
extern void rt_spin_lock_unlock(spinlock_t *lock);
extern int rt_spin_trylock_bh(spinlock_t *lock);
extern int rt_spin_trylock(spinlock_t *lock);
static __always_inline void spin_lock(spinlock_t *lock)
{
rt_spin_lock(lock);
}
#ifdef CONFIG_LOCKDEP
# define __spin_lock_nested(lock, subclass) \
rt_spin_lock_nested(lock, subclass)
# define __spin_lock_nest_lock(lock, nest_lock) \
do { \
typecheck(struct lockdep_map *, &(nest_lock)->dep_map); \
rt_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
} while (0)
# define __spin_lock_irqsave_nested(lock, flags, subclass) \
do { \
typecheck(unsigned long, flags); \
flags = 0; \
__spin_lock_nested(lock, subclass); \
} while (0)
#else
/*
* Always evaluate the 'subclass' argument to avoid that the compiler
* warns about set-but-not-used variables when building with
* CONFIG_DEBUG_LOCK_ALLOC=n and with W=1.
*/
# define __spin_lock_nested(lock, subclass) spin_lock(((void)(subclass), (lock)))
# define __spin_lock_nest_lock(lock, subclass) spin_lock(((void)(subclass), (lock)))
# define __spin_lock_irqsave_nested(lock, flags, subclass) \
spin_lock_irqsave(((void)(subclass), (lock)), flags)
#endif
#define spin_lock_nested(lock, subclass) \
__spin_lock_nested(lock, subclass)
#define spin_lock_nest_lock(lock, nest_lock) \
__spin_lock_nest_lock(lock, nest_lock)
#define spin_lock_irqsave_nested(lock, flags, subclass) \
__spin_lock_irqsave_nested(lock, flags, subclass)
static __always_inline void spin_lock_bh(spinlock_t *lock)
{
/* Investigate: Drop bh when blocking ? */
local_bh_disable();
rt_spin_lock(lock);
}
static __always_inline void spin_lock_irq(spinlock_t *lock)
{
rt_spin_lock(lock);
}
#define spin_lock_irqsave(lock, flags) \
do { \
typecheck(unsigned long, flags); \
flags = 0; \
spin_lock(lock); \
} while (0)
static __always_inline void spin_unlock(spinlock_t *lock)
{
rt_spin_unlock(lock);
}
static __always_inline void spin_unlock_bh(spinlock_t *lock)
{
rt_spin_unlock(lock);
local_bh_enable();
}
static __always_inline void spin_unlock_irq(spinlock_t *lock)
{
rt_spin_unlock(lock);
}
static __always_inline void spin_unlock_irqrestore(spinlock_t *lock,
unsigned long flags)
{
rt_spin_unlock(lock);
}
#define spin_trylock(lock) \
__cond_lock(lock, rt_spin_trylock(lock))
#define spin_trylock_bh(lock) \
__cond_lock(lock, rt_spin_trylock_bh(lock))
#define spin_trylock_irq(lock) \
__cond_lock(lock, rt_spin_trylock(lock))
#define __spin_trylock_irqsave(lock, flags) \
({ \
int __locked; \
\
typecheck(unsigned long, flags); \
flags = 0; \
__locked = spin_trylock(lock); \
__locked; \
})
#define spin_trylock_irqsave(lock, flags) \
__cond_lock(lock, __spin_trylock_irqsave(lock, flags))
#define spin_is_contended(lock) (((void)(lock), 0))
static inline int spin_is_locked(spinlock_t *lock)
{
return rt_mutex_base_is_locked(&lock->lock);
}
#define assert_spin_locked(lock) BUG_ON(!spin_is_locked(lock))
#endif