mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-16 07:24:39 +08:00
f44ca0871b
When building with W=2, the build log is flooded with
include/asm-generic/qrwlock.h:65:56: warning: pointer targets in passing argument 2 of 'atomic_try_cmpxchg_acquire' differ in signedness [-Wpointer-sign]
include/asm-generic/qrwlock.h:92:53: warning: pointer targets in passing argument 2 of 'atomic_try_cmpxchg_acquire' differ in signedness [-Wpointer-sign]
include/asm-generic/qspinlock.h:68:55: warning: pointer targets in passing argument 2 of 'atomic_try_cmpxchg_acquire' differ in signedness [-Wpointer-sign]
include/asm-generic/qspinlock.h:82:52: warning: pointer targets in passing argument 2 of 'atomic_try_cmpxchg_acquire' differ in signedness [-Wpointer-sign]
The atomics are built on top of signed integers, but the caller
doesn't actually care. Just use signed types as well.
Fixes: 27df89689e ("locking/spinlocks: Remove an instruction from spin and write locks")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
122 lines
3.3 KiB
C
122 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
|
|
/*
|
|
* Queued spinlock
|
|
*
|
|
* (C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P.
|
|
* (C) Copyright 2015 Hewlett-Packard Enterprise Development LP
|
|
*
|
|
* Authors: Waiman Long <waiman.long@hpe.com>
|
|
*/
|
|
#ifndef __ASM_GENERIC_QSPINLOCK_H
|
|
#define __ASM_GENERIC_QSPINLOCK_H
|
|
|
|
#include <asm-generic/qspinlock_types.h>
|
|
#include <linux/atomic.h>
|
|
|
|
#ifndef queued_spin_is_locked
|
|
/**
|
|
* queued_spin_is_locked - is the spinlock locked?
|
|
* @lock: Pointer to queued spinlock structure
|
|
* Return: 1 if it is locked, 0 otherwise
|
|
*/
|
|
static __always_inline int queued_spin_is_locked(struct qspinlock *lock)
|
|
{
|
|
/*
|
|
* Any !0 state indicates it is locked, even if _Q_LOCKED_VAL
|
|
* isn't immediately observable.
|
|
*/
|
|
return atomic_read(&lock->val);
|
|
}
|
|
#endif
|
|
|
|
/**
|
|
* queued_spin_value_unlocked - is the spinlock structure unlocked?
|
|
* @lock: queued spinlock structure
|
|
* Return: 1 if it is unlocked, 0 otherwise
|
|
*
|
|
* N.B. Whenever there are tasks waiting for the lock, it is considered
|
|
* locked wrt the lockref code to avoid lock stealing by the lockref
|
|
* code and change things underneath the lock. This also allows some
|
|
* optimizations to be applied without conflict with lockref.
|
|
*/
|
|
static __always_inline int queued_spin_value_unlocked(struct qspinlock lock)
|
|
{
|
|
return !atomic_read(&lock.val);
|
|
}
|
|
|
|
/**
|
|
* queued_spin_is_contended - check if the lock is contended
|
|
* @lock : Pointer to queued spinlock structure
|
|
* Return: 1 if lock contended, 0 otherwise
|
|
*/
|
|
static __always_inline int queued_spin_is_contended(struct qspinlock *lock)
|
|
{
|
|
return atomic_read(&lock->val) & ~_Q_LOCKED_MASK;
|
|
}
|
|
/**
|
|
* queued_spin_trylock - try to acquire the queued spinlock
|
|
* @lock : Pointer to queued spinlock structure
|
|
* Return: 1 if lock acquired, 0 if failed
|
|
*/
|
|
static __always_inline int queued_spin_trylock(struct qspinlock *lock)
|
|
{
|
|
int val = atomic_read(&lock->val);
|
|
|
|
if (unlikely(val))
|
|
return 0;
|
|
|
|
return likely(atomic_try_cmpxchg_acquire(&lock->val, &val, _Q_LOCKED_VAL));
|
|
}
|
|
|
|
extern void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
|
|
|
|
#ifndef queued_spin_lock
|
|
/**
|
|
* queued_spin_lock - acquire a queued spinlock
|
|
* @lock: Pointer to queued spinlock structure
|
|
*/
|
|
static __always_inline void queued_spin_lock(struct qspinlock *lock)
|
|
{
|
|
int val = 0;
|
|
|
|
if (likely(atomic_try_cmpxchg_acquire(&lock->val, &val, _Q_LOCKED_VAL)))
|
|
return;
|
|
|
|
queued_spin_lock_slowpath(lock, val);
|
|
}
|
|
#endif
|
|
|
|
#ifndef queued_spin_unlock
|
|
/**
|
|
* queued_spin_unlock - release a queued spinlock
|
|
* @lock : Pointer to queued spinlock structure
|
|
*/
|
|
static __always_inline void queued_spin_unlock(struct qspinlock *lock)
|
|
{
|
|
/*
|
|
* unlock() needs release semantics:
|
|
*/
|
|
smp_store_release(&lock->locked, 0);
|
|
}
|
|
#endif
|
|
|
|
#ifndef virt_spin_lock
|
|
static __always_inline bool virt_spin_lock(struct qspinlock *lock)
|
|
{
|
|
return false;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Remapping spinlock architecture specific functions to the corresponding
|
|
* queued spinlock functions.
|
|
*/
|
|
#define arch_spin_is_locked(l) queued_spin_is_locked(l)
|
|
#define arch_spin_is_contended(l) queued_spin_is_contended(l)
|
|
#define arch_spin_value_unlocked(l) queued_spin_value_unlocked(l)
|
|
#define arch_spin_lock(l) queued_spin_lock(l)
|
|
#define arch_spin_trylock(l) queued_spin_trylock(l)
|
|
#define arch_spin_unlock(l) queued_spin_unlock(l)
|
|
|
|
#endif /* __ASM_GENERIC_QSPINLOCK_H */
|