1#ifndef __IOPRIO_H__
2#define	__IOPRIO_H__
3
4//----------------------------------------------------------------------------
5// Copy of the 2.6.18 kernel header (linux/ioprio.h)
6//
7
8/*
9 * Gives us 8 prio classes with 13-bits of data for each class
10 */
11#define IOPRIO_BITS		(16)
12#define IOPRIO_CLASS_SHIFT	(13)
13#define IOPRIO_PRIO_MASK	((1UL << IOPRIO_CLASS_SHIFT) - 1)
14
15#define IOPRIO_PRIO_CLASS(mask)	((mask) >> IOPRIO_CLASS_SHIFT)
16#define IOPRIO_PRIO_DATA(mask)	((mask) & IOPRIO_PRIO_MASK)
17#define IOPRIO_PRIO_VALUE(class, data)	(((class) << IOPRIO_CLASS_SHIFT) | data)
18
19#define ioprio_valid(mask)	(IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE)
20
21/*
22 * These are the io priority groups as implemented by CFQ. RT is the realtime
23 * class, it always gets premium service. BE is the best-effort scheduling
24 * class, the default for any process. IDLE is the idle scheduling class, it
25 * is only served when no one else is using the disk.
26 */
27enum {
28	IOPRIO_CLASS_NONE,
29	IOPRIO_CLASS_RT,
30	IOPRIO_CLASS_BE,
31	IOPRIO_CLASS_IDLE,
32};
33
34/*
35 * 8 best effort priority levels are supported
36 */
37#define IOPRIO_BE_NR	(8)
38
39enum {
40	IOPRIO_WHO_PROCESS = 1,
41	IOPRIO_WHO_PGRP,
42	IOPRIO_WHO_USER,
43};
44//-----------------------------------------------------------------------------
45
46#endif /* __IOPRIO_H__ */
47