diff options
Diffstat (limited to 'include/linux/smp_lock.h')
| -rw-r--r-- | include/linux/smp_lock.h | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/include/linux/smp_lock.h b/include/linux/smp_lock.h new file mode 100644 index 000000000000..b63ce7014093 --- /dev/null +++ b/include/linux/smp_lock.h @@ -0,0 +1,54 @@ +#ifndef __LINUX_SMPLOCK_H +#define __LINUX_SMPLOCK_H + +#include <linux/config.h> +#include <linux/sched.h> +#include <linux/spinlock.h> + +#ifdef CONFIG_LOCK_KERNEL + +#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 */ |