1#ifndef _UAPI_LINUX_IOPRIO_H
2#define _UAPI_LINUX_IOPRIO_H
3
4/*
5 * Gives us 8 prio classes with 13-bits of data for each class
6 */
7#define IOPRIO_BITS		(16)
8#define IOPRIO_CLASS_SHIFT	(13)
9#define IOPRIO_PRIO_MASK	((1UL << IOPRIO_CLASS_SHIFT) - 1)
10
11#define IOPRIO_PRIO_CLASS(mask)	((mask) >> IOPRIO_CLASS_SHIFT)
12#define IOPRIO_PRIO_DATA(mask)	((mask) & IOPRIO_PRIO_MASK)
13#define IOPRIO_PRIO_VALUE(class, data)	(((class) << IOPRIO_CLASS_SHIFT) | data)
14
15#define ioprio_valid(mask)	(IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE)
16
17/*
18 * These are the io priority groups as implemented by CFQ. RT is the realtime
19 * class, it always gets premium service. BE is the best-effort scheduling
20 * class, the default for any process. IDLE is the idle scheduling class, it
21 * is only served when no one else is using the disk.
22 */
23enum {
24	IOPRIO_CLASS_NONE,
25	IOPRIO_CLASS_RT,
26	IOPRIO_CLASS_BE,
27	IOPRIO_CLASS_IDLE,
28};
29
30/*
31 * 8 best effort priority levels are supported
32 */
33#define IOPRIO_BE_NR	(8)
34
35enum {
36	IOPRIO_WHO_PROCESS = 1,
37	IOPRIO_WHO_PGRP,
38	IOPRIO_WHO_USER,
39};
40
41/*
42 * Fallback BE priority
43 */
44#define IOPRIO_NORM	(4)
45
46#endif /* _UAPI_LINUX_IOPRIO_H */
47