Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1#ifndef __LINUX_SMPLOCK_H
2#define __LINUX_SMPLOCK_H
3
4#include <linux/config.h>
5#include <linux/sched.h>
6#include <linux/spinlock.h>
7
8#ifdef CONFIG_LOCK_KERNEL
9
10#define kernel_locked() (current->lock_depth >= 0)
11
12extern int __lockfunc __reacquire_kernel_lock(void);
13extern void __lockfunc __release_kernel_lock(void);
14
15/*
16 * Release/re-acquire global kernel lock for the scheduler
17 */
18#define release_kernel_lock(tsk) do { \
19 if (unlikely((tsk)->lock_depth >= 0)) \
20 __release_kernel_lock(); \
21} while (0)
22
23/*
24 * Non-SMP kernels will never block on the kernel lock,
25 * so we are better off returning a constant zero from
26 * reacquire_kernel_lock() so that the compiler can see
27 * it at compile-time.
28 */
29#if defined(CONFIG_SMP) && !defined(CONFIG_PREEMPT_BKL)
30# define return_value_on_smp return
31#else
32# define return_value_on_smp
33#endif
34
35static inline int reacquire_kernel_lock(struct task_struct *task)
36{
37 if (unlikely(task->lock_depth >= 0))
38 return_value_on_smp __reacquire_kernel_lock();
39 return 0;
40}
41
42extern void __lockfunc lock_kernel(void) __acquires(kernel_lock);
43extern void __lockfunc unlock_kernel(void) __releases(kernel_lock);
44
45#else
46
47#define lock_kernel() do { } while(0)
48#define unlock_kernel() do { } while(0)
49#define release_kernel_lock(task) do { } while(0)
50#define reacquire_kernel_lock(task) 0
51#define kernel_locked() 1
52
53#endif /* CONFIG_LOCK_KERNEL */
54#endif /* __LINUX_SMPLOCK_H */