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