linux-stable/include/linux/spinlock_up.h
Nataniel Farzan a7306f3c28 Improve consistency of '#error' directive messages
Remove the use of contractions and use proper punctuation in #error
directive messages that discourage the direct inclusion of header files.

Link: https://lkml.kernel.org/r/20241105032231.28833-1-natanielfarzan@gmail.com
Signed-off-by: Nataniel Farzan <natanielfarzan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-11-11 17:17:04 -08:00

72 lines
2.1 KiB
C

#ifndef __LINUX_SPINLOCK_UP_H
#define __LINUX_SPINLOCK_UP_H
#ifndef __LINUX_INSIDE_SPINLOCK_H
# error "Please do not include this file directly."
#endif
#include <asm/processor.h> /* for cpu_relax() */
#include <asm/barrier.h>
/*
* include/linux/spinlock_up.h - UP-debug version of spinlocks.
*
* portions Copyright 2005, Red Hat, Inc., Ingo Molnar
* Released under the General Public License (GPL).
*
* In the debug case, 1 means unlocked, 0 means locked. (the values
* are inverted, to catch initialization bugs)
*
* No atomicity anywhere, we are on UP. However, we still need
* the compiler barriers, because we do not want the compiler to
* move potentially faulting instructions (notably user accesses)
* into the locked sequence, resulting in non-atomic execution.
*/
#ifdef CONFIG_DEBUG_SPINLOCK
#define arch_spin_is_locked(x) ((x)->slock == 0)
static inline void arch_spin_lock(arch_spinlock_t *lock)
{
lock->slock = 0;
barrier();
}
static inline int arch_spin_trylock(arch_spinlock_t *lock)
{
char oldval = lock->slock;
lock->slock = 0;
barrier();
return oldval > 0;
}
static inline void arch_spin_unlock(arch_spinlock_t *lock)
{
barrier();
lock->slock = 1;
}
/*
* Read-write spinlocks. No debug version.
*/
#define arch_read_lock(lock) do { barrier(); (void)(lock); } while (0)
#define arch_write_lock(lock) do { barrier(); (void)(lock); } while (0)
#define arch_read_trylock(lock) ({ barrier(); (void)(lock); 1; })
#define arch_write_trylock(lock) ({ barrier(); (void)(lock); 1; })
#define arch_read_unlock(lock) do { barrier(); (void)(lock); } while (0)
#define arch_write_unlock(lock) do { barrier(); (void)(lock); } while (0)
#else /* DEBUG_SPINLOCK */
#define arch_spin_is_locked(lock) ((void)(lock), 0)
/* for sched/core.c and kernel_lock.c: */
# define arch_spin_lock(lock) do { barrier(); (void)(lock); } while (0)
# define arch_spin_unlock(lock) do { barrier(); (void)(lock); } while (0)
# define arch_spin_trylock(lock) ({ barrier(); (void)(lock); 1; })
#endif /* DEBUG_SPINLOCK */
#define arch_spin_is_contended(lock) (((void)(lock), 0))
#endif /* __LINUX_SPINLOCK_UP_H */