include/litmus/locking.h


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#ifndef LITMUS_LOCKING_H
#define LITMUS_LOCKING_H

#include <litmus/fdso.h>

struct litmus_lock_ops;

extern struct fdso_ops generic_lock_ops;

/* Generic base struct for LITMUS^RT userspace semaphores.
 * This structure should be embedded in protocol-specific semaphores.
 */
struct litmus_lock {
	struct litmus_lock_ops *ops;
	int type;
};

struct litmus_lock_ops {
	/* Current task tries to obtain / drop a reference to a lock.
	 * Optional methods, allowed by default. */
	int (*open)(struct litmus_lock*, void* __user);
	int (*close)(struct litmus_lock*);
    
	/* Current tries to lock/unlock this lock (mandatory methods). */
	int (*lock)(struct litmus_lock*);
	int (*unlock)(struct litmus_lock*);

    int (*dynamic_group_lock)(struct litmus_lock*, resource_mask_t);
    int (*dynamic_group_unlock)(struct litmus_lock*, resource_mask_t);

	/* The lock is no longer being referenced (mandatory method). */
	void (*deallocate)(struct litmus_lock*);
};

static inline bool is_lock(struct od_table_entry* entry)
{
	return entry->class == &generic_lock_ops;
}

static inline struct litmus_lock* get_lock(struct od_table_entry* entry)
{
	BUG_ON(!is_lock(entry));
	return (struct litmus_lock*) entry->obj->obj;
}

#endif