mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 19:29:37 +00:00
![Dan Streetman](/assets/img/avatar_default.png)
Move the __ARCH_SPIN_LOCK_UNLOCKED definition from qspinlock.h into qspinlock_types.h. The definition of __ARCH_SPIN_LOCK_UNLOCKED comes from the build arch's include files; but on x86 when CONFIG_QUEUED_SPINLOCKS=y, it just it's defined in asm-generic/qspinlock.h. In most cases, this doesn't matter because linux/spinlock.h includes asm/spinlock.h, which for x86 includes asm-generic/qspinlock.h. However, any code that only includes linux/mutex.h will break, because it only includes asm/spinlock_types.h. For example, this breaks systemtap, which only includes mutex.h. Signed-off-by: Dan Streetman <dan.streetman@canonical.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Waiman Long <Waiman.Long@hpe.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1455907767-17821-1-git-send-email-dan.streetman@canonical.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
84 lines
2.3 KiB
C
84 lines
2.3 KiB
C
/*
|
|
* Queued spinlock
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* (C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P.
|
|
*
|
|
* Authors: Waiman Long <waiman.long@hp.com>
|
|
*/
|
|
#ifndef __ASM_GENERIC_QSPINLOCK_TYPES_H
|
|
#define __ASM_GENERIC_QSPINLOCK_TYPES_H
|
|
|
|
/*
|
|
* Including atomic.h with PARAVIRT on will cause compilation errors because
|
|
* of recursive header file incluson via paravirt_types.h. So don't include
|
|
* it if PARAVIRT is on.
|
|
*/
|
|
#ifndef CONFIG_PARAVIRT
|
|
#include <linux/types.h>
|
|
#include <linux/atomic.h>
|
|
#endif
|
|
|
|
typedef struct qspinlock {
|
|
atomic_t val;
|
|
} arch_spinlock_t;
|
|
|
|
/*
|
|
* Initializier
|
|
*/
|
|
#define __ARCH_SPIN_LOCK_UNLOCKED { ATOMIC_INIT(0) }
|
|
|
|
/*
|
|
* Bitfields in the atomic value:
|
|
*
|
|
* When NR_CPUS < 16K
|
|
* 0- 7: locked byte
|
|
* 8: pending
|
|
* 9-15: not used
|
|
* 16-17: tail index
|
|
* 18-31: tail cpu (+1)
|
|
*
|
|
* When NR_CPUS >= 16K
|
|
* 0- 7: locked byte
|
|
* 8: pending
|
|
* 9-10: tail index
|
|
* 11-31: tail cpu (+1)
|
|
*/
|
|
#define _Q_SET_MASK(type) (((1U << _Q_ ## type ## _BITS) - 1)\
|
|
<< _Q_ ## type ## _OFFSET)
|
|
#define _Q_LOCKED_OFFSET 0
|
|
#define _Q_LOCKED_BITS 8
|
|
#define _Q_LOCKED_MASK _Q_SET_MASK(LOCKED)
|
|
|
|
#define _Q_PENDING_OFFSET (_Q_LOCKED_OFFSET + _Q_LOCKED_BITS)
|
|
#if CONFIG_NR_CPUS < (1U << 14)
|
|
#define _Q_PENDING_BITS 8
|
|
#else
|
|
#define _Q_PENDING_BITS 1
|
|
#endif
|
|
#define _Q_PENDING_MASK _Q_SET_MASK(PENDING)
|
|
|
|
#define _Q_TAIL_IDX_OFFSET (_Q_PENDING_OFFSET + _Q_PENDING_BITS)
|
|
#define _Q_TAIL_IDX_BITS 2
|
|
#define _Q_TAIL_IDX_MASK _Q_SET_MASK(TAIL_IDX)
|
|
|
|
#define _Q_TAIL_CPU_OFFSET (_Q_TAIL_IDX_OFFSET + _Q_TAIL_IDX_BITS)
|
|
#define _Q_TAIL_CPU_BITS (32 - _Q_TAIL_CPU_OFFSET)
|
|
#define _Q_TAIL_CPU_MASK _Q_SET_MASK(TAIL_CPU)
|
|
|
|
#define _Q_TAIL_OFFSET _Q_TAIL_IDX_OFFSET
|
|
#define _Q_TAIL_MASK (_Q_TAIL_IDX_MASK | _Q_TAIL_CPU_MASK)
|
|
|
|
#define _Q_LOCKED_VAL (1U << _Q_LOCKED_OFFSET)
|
|
#define _Q_PENDING_VAL (1U << _Q_PENDING_OFFSET)
|
|
|
|
#endif /* __ASM_GENERIC_QSPINLOCK_TYPES_H */
|