mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-29 15:43:59 +08:00
95c354fe9f
The break_lock data structure and code for spinlocks is quite nasty. Not only does it double the size of a spinlock but it changes locking to a potentially less optimal trylock. Put all of that under CONFIG_GENERIC_LOCKBREAK, and introduce a __raw_spin_is_contended that uses the lock data itself to determine whether there are waiters on the lock, to be used if CONFIG_GENERIC_LOCKBREAK is not set. Rename need_lockbreak to spin_needbreak, make it use spin_is_contended to decouple it from the spinlock implementation, and make it typesafe (rwlocks do not have any need_lockbreak sites -- why do they even get bloated up with that break_lock then?). Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
76 lines
2.0 KiB
C
76 lines
2.0 KiB
C
#ifndef __LINUX_SPINLOCK_UP_H
|
|
#define __LINUX_SPINLOCK_UP_H
|
|
|
|
#ifndef __LINUX_SPINLOCK_H
|
|
# error "please don't include this file directly"
|
|
#endif
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
|
|
#ifdef CONFIG_DEBUG_SPINLOCK
|
|
#define __raw_spin_is_locked(x) ((x)->slock == 0)
|
|
|
|
static inline void __raw_spin_lock(raw_spinlock_t *lock)
|
|
{
|
|
lock->slock = 0;
|
|
}
|
|
|
|
static inline void
|
|
__raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
|
|
{
|
|
local_irq_save(flags);
|
|
lock->slock = 0;
|
|
}
|
|
|
|
static inline int __raw_spin_trylock(raw_spinlock_t *lock)
|
|
{
|
|
char oldval = lock->slock;
|
|
|
|
lock->slock = 0;
|
|
|
|
return oldval > 0;
|
|
}
|
|
|
|
static inline void __raw_spin_unlock(raw_spinlock_t *lock)
|
|
{
|
|
lock->slock = 1;
|
|
}
|
|
|
|
/*
|
|
* Read-write spinlocks. No debug version.
|
|
*/
|
|
#define __raw_read_lock(lock) do { (void)(lock); } while (0)
|
|
#define __raw_write_lock(lock) do { (void)(lock); } while (0)
|
|
#define __raw_read_trylock(lock) ({ (void)(lock); 1; })
|
|
#define __raw_write_trylock(lock) ({ (void)(lock); 1; })
|
|
#define __raw_read_unlock(lock) do { (void)(lock); } while (0)
|
|
#define __raw_write_unlock(lock) do { (void)(lock); } while (0)
|
|
|
|
#else /* DEBUG_SPINLOCK */
|
|
#define __raw_spin_is_locked(lock) ((void)(lock), 0)
|
|
/* for sched.c and kernel_lock.c: */
|
|
# define __raw_spin_lock(lock) do { (void)(lock); } while (0)
|
|
# define __raw_spin_unlock(lock) do { (void)(lock); } while (0)
|
|
# define __raw_spin_trylock(lock) ({ (void)(lock); 1; })
|
|
#endif /* DEBUG_SPINLOCK */
|
|
|
|
#define __raw_spin_is_contended(lock) (((void)(lock), 0))
|
|
|
|
#define __raw_read_can_lock(lock) (((void)(lock), 1))
|
|
#define __raw_write_can_lock(lock) (((void)(lock), 1))
|
|
|
|
#define __raw_spin_unlock_wait(lock) \
|
|
do { cpu_relax(); } while (__raw_spin_is_locked(lock))
|
|
|
|
#endif /* __LINUX_SPINLOCK_UP_H */
|