linux-stable/include/linux/spinlock_rt.h
Sebastian Andrzej Siewior 2747b93ebb locking: Detect includes rwlock.h outside of spinlock.h
From: Michael S. Tsirkin <mst@redhat.com>

The check for __LINUX_SPINLOCK_H within rwlock.h (and other files)
detects the direct include of the header file if it is at the very
beginning of the include section.
If it is listed later then chances are high that spinlock.h was already
included (including rwlock.h) and the additional listing of rwlock.h
will not cause any failure.

On PREEMPT_RT this additional rwlock.h will lead to compile failures
since it uses a different rwlock implementation.

Add __LINUX_INSIDE_SPINLOCK_H to spinlock.h and check for this instead
of __LINUX_SPINLOCK_H to detect wrong includes. This will help detect
direct includes of rwlock.h with without PREEMPT_RT enabled.

[ bigeasy: add remaining __LINUX_SPINLOCK_H user and rewrite
  commit description. ]

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YweemHxJx7O8rjBx@linutronix.de
2022-09-15 16:14:02 +02:00

159 lines
4.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
#ifndef __LINUX_SPINLOCK_RT_H
#define __LINUX_SPINLOCK_RT_H
#ifndef __LINUX_INSIDE_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, bool percpu);
#else
static inline void __rt_spin_lock_init(spinlock_t *lock, const char *name,
struct lock_class_key *key, bool percpu)
{
}
#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, false); \
} while (0)
#define local_spin_lock_init(slock) \
do { \
static struct lock_class_key __key; \
\
rt_mutex_base_init(&(slock)->lock); \
__rt_spin_lock_init(slock, #slock, &__key, true); \
} 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))
#include <linux/rwlock_rt.h>
#endif