Linux Kernel input evdev

struct evdev {
	int open;
	struct input_handle handle;
	wait_queue_head_t wait;
	struct evdev_client __rcu *grab;
	struct list_head client_list;
	spinlock_t client_lock; /* protects client_list */
	struct mutex mutex;
	struct device dev;
	struct cdev cdev;
	bool exist;
};
 
struct evdev_client {
	unsigned int head;
	unsigned int tail;
	unsigned int packet_head; /* [future] position of the first element of next packet */
	spinlock_t buffer_lock; /* protects access to buffer, head and tail */
	struct fasync_struct *fasync;
	struct evdev *evdev;
	struct list_head node;
	unsigned int clk_type;
	bool revoked;
	unsigned long *evmasks[EV_CNT];
	unsigned int bufsize;
	struct input_event buffer[];
};