Current File : //usr/src/blksnap-6.3.0.73/event_queue.h
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __BLK_SNAP_EVENT_QUEUE_H
#define __BLK_SNAP_EVENT_QUEUE_H
#include <linux/types.h>
#include <linux/ktime.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
/**
* struct event - An event to be passed to the user space.
* @link:
* The list header allows to combine events from the queue.
* @time:
* A timestamp indicates when an event occurred.
* @code:
* Event code.
* @data_size:
* The number of bytes in the event data array.
* @data:
* An array of event data.
*
* Events can be different, so they contain different data. The size of the
* data array is not defined exactly, but it has limitations. The size of
* the event structure may exceed the PAGE_SIZE.
*/
struct event {
struct list_head link;
ktime_t time;
int code;
int data_size;
char data[]; /* up to PAGE_SIZE - sizeof(struct blk_snap_snapshot_event) */
};
/**
* struct event_queue - A queue of &struct event.
* @list:
* Linked list for storing events.
* @lock:
* Spinlock allows to guarantee safety of the linked list.
* @wq_head:
* A wait queue allows to put a user thread in a waiting state until
* an event appears in the linked list.
*/
struct event_queue {
struct list_head list;
spinlock_t lock;
struct wait_queue_head wq_head;
};
void event_queue_init(struct event_queue *event_queue);
void event_queue_done(struct event_queue *event_queue);
int event_gen(struct event_queue *event_queue, gfp_t flags, int code,
const void *data, int data_size);
struct event *event_wait(struct event_queue *event_queue,
unsigned long timeout_ms);
static inline void event_free(struct event *event)
{
kfree(event);
if (event)
memory_object_dec(memory_object_event);
};
#endif /* __BLK_SNAP_EVENT_QUEUE_H */
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