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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  */
27 enum {
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 
39 enum {
40 	IOPRIO_WHO_PROCESS = 1,
41 	IOPRIO_WHO_PGRP,
42 	IOPRIO_WHO_USER,
43 };
44 //-----------------------------------------------------------------------------
45 
46 #endif /* __IOPRIO_H__ */
47