1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux 1
2 #ifndef _UAPI_LINUX_IOPRIO_H
3 #define _UAPI_LINUX_IOPRIO_H
4
5 #include <linux/stddef.h>
6 #include <linux/types.h>
7
8 /*
9 * Gives us 8 prio classes with 13-bits of dat
10 */
11 #define IOPRIO_CLASS_SHIFT 13
12 #define IOPRIO_NR_CLASSES 8
13 #define IOPRIO_CLASS_MASK (IOPRIO_NR_CLA
14 #define IOPRIO_PRIO_MASK ((1UL << IOPRI
15
16 #define IOPRIO_PRIO_CLASS(ioprio) \
17 (((ioprio) >> IOPRIO_CLASS_SHIFT) & IO
18 #define IOPRIO_PRIO_DATA(ioprio) ((iopr
19
20 /*
21 * These are the io priority classes as implem
22 * schedulers. RT is the realtime class, it al
23 * ATA disks supporting NCQ IO priority, RT cl
24 * high priority NCQ commands. BE is the best-
25 * default for any process. IDLE is the idle s
26 * served when no one else is using the disk.
27 */
28 enum {
29 IOPRIO_CLASS_NONE = 0,
30 IOPRIO_CLASS_RT = 1,
31 IOPRIO_CLASS_BE = 2,
32 IOPRIO_CLASS_IDLE = 3,
33
34 /* Special class to indicate an invali
35 IOPRIO_CLASS_INVALID = 7,
36 };
37
38 /*
39 * The RT and BE priority classes both support
40 * can be specified using the lower 3-bits of
41 */
42 #define IOPRIO_LEVEL_NR_BITS 3
43 #define IOPRIO_NR_LEVELS (1 <<
44 #define IOPRIO_LEVEL_MASK (IOPRI
45 #define IOPRIO_PRIO_LEVEL(ioprio) ((iopr
46
47 #define IOPRIO_BE_NR IOPRIO
48
49 /*
50 * Possible values for the "which" argument of
51 * ioprio_set() system calls (see "man ioprio_
52 */
53 enum {
54 IOPRIO_WHO_PROCESS = 1,
55 IOPRIO_WHO_PGRP,
56 IOPRIO_WHO_USER,
57 };
58
59 /*
60 * Fallback BE class priority level.
61 */
62 #define IOPRIO_NORM 4
63 #define IOPRIO_BE_NORM IOPRIO_NORM
64
65 /*
66 * The 10 bits between the priority class and
67 * optionally define I/O hints for any combina
68 * level. Depending on the kernel configuratio
69 * the target I/O device being used, hints can
70 * without affecting the I/O scheduling orderi
71 * class and level.
72 */
73 #define IOPRIO_HINT_SHIFT IOPRIO
74 #define IOPRIO_HINT_NR_BITS 10
75 #define IOPRIO_NR_HINTS (1 <<
76 #define IOPRIO_HINT_MASK (IOPRI
77 #define IOPRIO_PRIO_HINT(ioprio) \
78 (((ioprio) >> IOPRIO_HINT_SHIFT) & IOP
79
80 /*
81 * I/O hints.
82 */
83 enum {
84 /* No hint */
85 IOPRIO_HINT_NONE = 0,
86
87 /*
88 * Device command duration limits: ind
89 * duration limit for the commands tha
90 * These will currently only be effect
91 * support the command duration limits
92 * enabled, then the commands issued t
93 * one of these hints set will have th
94 * set to the value of the hint.
95 */
96 IOPRIO_HINT_DEV_DURATION_LIMIT_1 = 1,
97 IOPRIO_HINT_DEV_DURATION_LIMIT_2 = 2,
98 IOPRIO_HINT_DEV_DURATION_LIMIT_3 = 3,
99 IOPRIO_HINT_DEV_DURATION_LIMIT_4 = 4,
100 IOPRIO_HINT_DEV_DURATION_LIMIT_5 = 5,
101 IOPRIO_HINT_DEV_DURATION_LIMIT_6 = 6,
102 IOPRIO_HINT_DEV_DURATION_LIMIT_7 = 7,
103 };
104
105 #define IOPRIO_BAD_VALUE(val, max) ((val) < 0
106
107 /*
108 * Return an I/O priority value based on a cla
109 */
110 static __always_inline __u16 ioprio_value(int
111 int
112 {
113 if (IOPRIO_BAD_VALUE(prioclass, IOPRIO
114 IOPRIO_BAD_VALUE(priolevel, IOPRIO
115 IOPRIO_BAD_VALUE(priohint, IOPRIO_
116 return IOPRIO_CLASS_INVALID <<
117
118 return (prioclass << IOPRIO_CLASS_SHIF
119 (priohint << IOPRIO_HINT_SHIFT
120 }
121
122 #define IOPRIO_PRIO_VALUE(prioclass, priolevel
123 ioprio_value(prioclass, priolevel, IOP
124 #define IOPRIO_PRIO_VALUE_HINT(prioclass, prio
125 ioprio_value(prioclass, priolevel, pri
126
127 #endif /* _UAPI_LINUX_IOPRIO_H */
128
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.