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linux-next/include/linux/smp_lock.h
Al Viro f037360f2e [PATCH] m68k: thread_info header cleanup
a) in smp_lock.h #include of sched.h and spinlock.h moved under #ifdef
   CONFIG_LOCK_KERNEL.

b) interrupt.h now explicitly pulls sched.h (not via smp_lock.h from
   hardirq.h as it used to)

c) in three more places we need changes to compensate for (a) - one place
   in arch/sparc needs string.h now, hardirq.h needs forward declaration of
   task_struct and preempt.h needs direct include of thread_info.h.

d) thread_info-related helpers in sched.h and thread_info.h put under
   ifndef __HAVE_THREAD_FUNCTIONS.  Obviously safe.

Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-13 18:14:13 -08:00

54 lines
1.4 KiB
C

#ifndef __LINUX_SMPLOCK_H
#define __LINUX_SMPLOCK_H
#include <linux/config.h>
#ifdef CONFIG_LOCK_KERNEL
#include <linux/sched.h>
#include <linux/spinlock.h>
#define kernel_locked() (current->lock_depth >= 0)
extern int __lockfunc __reacquire_kernel_lock(void);
extern void __lockfunc __release_kernel_lock(void);
/*
* Release/re-acquire global kernel lock for the scheduler
*/
#define release_kernel_lock(tsk) do { \
if (unlikely((tsk)->lock_depth >= 0)) \
__release_kernel_lock(); \
} while (0)
/*
* Non-SMP kernels will never block on the kernel lock,
* so we are better off returning a constant zero from
* reacquire_kernel_lock() so that the compiler can see
* it at compile-time.
*/
#if defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_BKL)
# define return_value_on_smp return
#else
# define return_value_on_smp
#endif
static inline int reacquire_kernel_lock(struct task_struct *task)
{
if (unlikely(task->lock_depth >= 0))
return_value_on_smp __reacquire_kernel_lock();
return 0;
}
extern void __lockfunc lock_kernel(void) __acquires(kernel_lock);
extern void __lockfunc unlock_kernel(void) __releases(kernel_lock);
#else
#define lock_kernel() do { } while(0)
#define unlock_kernel() do { } while(0)
#define release_kernel_lock(task) do { } while(0)
#define reacquire_kernel_lock(task) 0
#define kernel_locked() 1
#endif /* CONFIG_LOCK_KERNEL */
#endif /* __LINUX_SMPLOCK_H */