| 1 | /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ |
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| 2 | #ifndef _UAPI_LINUX_IOPRIO_H |
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| 3 | #define _UAPI_LINUX_IOPRIO_H |
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| 4 | |
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| 5 | #include <linux/stddef.h> |
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| 6 | #include <linux/types.h> |
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| 7 | |
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| 8 | /* |
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| 9 | * Gives us 8 prio classes with 13-bits of data for each class |
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| 10 | */ |
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| 11 | #define IOPRIO_CLASS_SHIFT 13 |
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| 12 | #define IOPRIO_NR_CLASSES 8 |
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| 13 | #define IOPRIO_CLASS_MASK (IOPRIO_NR_CLASSES - 1) |
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| 14 | #define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1) |
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| 15 | |
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| 16 | #define IOPRIO_PRIO_CLASS(ioprio) \ |
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| 17 | (((ioprio) >> IOPRIO_CLASS_SHIFT) & IOPRIO_CLASS_MASK) |
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| 18 | #define IOPRIO_PRIO_DATA(ioprio) ((ioprio) & IOPRIO_PRIO_MASK) |
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| 19 | |
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| 20 | /* |
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| 21 | * These are the io priority classes as implemented by the BFQ and mq-deadline |
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| 22 | * schedulers. RT is the realtime class, it always gets premium service. For |
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| 23 | * ATA disks supporting NCQ IO priority, RT class IOs will be processed using |
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| 24 | * high priority NCQ commands. BE is the best-effort scheduling class, the |
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| 25 | * default for any process. IDLE is the idle scheduling class, it is only |
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| 26 | * served when no one else is using the disk. |
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| 27 | */ |
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| 28 | enum { |
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| 29 | IOPRIO_CLASS_NONE = 0, |
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| 30 | IOPRIO_CLASS_RT = 1, |
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| 31 | IOPRIO_CLASS_BE = 2, |
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| 32 | IOPRIO_CLASS_IDLE = 3, |
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| 33 | |
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| 34 | /* Special class to indicate an invalid ioprio value */ |
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| 35 | IOPRIO_CLASS_INVALID = 7, |
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| 36 | }; |
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| 37 | |
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| 38 | /* |
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| 39 | * The RT and BE priority classes both support up to 8 priority levels that |
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| 40 | * can be specified using the lower 3-bits of the priority data. |
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| 41 | */ |
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| 42 | #define IOPRIO_LEVEL_NR_BITS 3 |
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| 43 | #define IOPRIO_NR_LEVELS (1 << IOPRIO_LEVEL_NR_BITS) |
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| 44 | #define IOPRIO_LEVEL_MASK (IOPRIO_NR_LEVELS - 1) |
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| 45 | #define IOPRIO_PRIO_LEVEL(ioprio) ((ioprio) & IOPRIO_LEVEL_MASK) |
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| 46 | |
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| 47 | #define IOPRIO_BE_NR IOPRIO_NR_LEVELS |
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| 48 | |
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| 49 | /* |
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| 50 | * Possible values for the "which" argument of the ioprio_get() and |
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| 51 | * ioprio_set() system calls (see "man ioprio_set"). |
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| 52 | */ |
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| 53 | enum { |
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| 54 | IOPRIO_WHO_PROCESS = 1, |
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| 55 | IOPRIO_WHO_PGRP, |
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| 56 | IOPRIO_WHO_USER, |
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| 57 | }; |
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| 58 | |
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| 59 | /* |
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| 60 | * Fallback BE class priority level. |
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| 61 | */ |
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| 62 | #define IOPRIO_NORM 4 |
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| 63 | #define IOPRIO_BE_NORM IOPRIO_NORM |
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| 64 | |
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| 65 | /* |
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| 66 | * The 10 bits between the priority class and the priority level are used to |
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| 67 | * optionally define I/O hints for any combination of I/O priority class and |
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| 68 | * level. Depending on the kernel configuration, I/O scheduler being used and |
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| 69 | * the target I/O device being used, hints can influence how I/Os are processed |
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| 70 | * without affecting the I/O scheduling ordering defined by the I/O priority |
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| 71 | * class and level. |
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| 72 | */ |
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| 73 | #define IOPRIO_HINT_SHIFT IOPRIO_LEVEL_NR_BITS |
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| 74 | #define IOPRIO_HINT_NR_BITS 10 |
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| 75 | #define IOPRIO_NR_HINTS (1 << IOPRIO_HINT_NR_BITS) |
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| 76 | #define IOPRIO_HINT_MASK (IOPRIO_NR_HINTS - 1) |
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| 77 | #define IOPRIO_PRIO_HINT(ioprio) \ |
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| 78 | (((ioprio) >> IOPRIO_HINT_SHIFT) & IOPRIO_HINT_MASK) |
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| 79 | |
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| 80 | /* |
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| 81 | * I/O hints. |
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| 82 | */ |
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| 83 | enum { |
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| 84 | /* No hint */ |
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| 85 | IOPRIO_HINT_NONE = 0, |
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| 86 | |
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| 87 | /* |
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| 88 | * Device command duration limits: indicate to the device a desired |
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| 89 | * duration limit for the commands that will be used to process an I/O. |
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| 90 | * These will currently only be effective for SCSI and ATA devices that |
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| 91 | * support the command duration limits feature. If this feature is |
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| 92 | * enabled, then the commands issued to the device to process an I/O with |
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| 93 | * one of these hints set will have the duration limit index (dld field) |
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| 94 | * set to the value of the hint. |
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| 95 | */ |
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| 96 | IOPRIO_HINT_DEV_DURATION_LIMIT_1 = 1, |
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| 97 | IOPRIO_HINT_DEV_DURATION_LIMIT_2 = 2, |
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| 98 | IOPRIO_HINT_DEV_DURATION_LIMIT_3 = 3, |
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| 99 | IOPRIO_HINT_DEV_DURATION_LIMIT_4 = 4, |
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| 100 | IOPRIO_HINT_DEV_DURATION_LIMIT_5 = 5, |
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| 101 | IOPRIO_HINT_DEV_DURATION_LIMIT_6 = 6, |
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| 102 | IOPRIO_HINT_DEV_DURATION_LIMIT_7 = 7, |
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| 103 | }; |
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| 104 | |
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| 105 | #define IOPRIO_BAD_VALUE(val, max) ((val) < 0 || (val) >= (max)) |
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| 106 | |
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| 107 | /* |
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| 108 | * Return an I/O priority value based on a class, a level and a hint. |
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| 109 | */ |
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| 110 | static __always_inline __u16 ioprio_value(int prioclass, int priolevel, |
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| 111 | int priohint) |
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| 112 | { |
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| 113 | if (IOPRIO_BAD_VALUE(prioclass, IOPRIO_NR_CLASSES) || |
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| 114 | IOPRIO_BAD_VALUE(priolevel, IOPRIO_NR_LEVELS) || |
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| 115 | IOPRIO_BAD_VALUE(priohint, IOPRIO_NR_HINTS)) |
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| 116 | return IOPRIO_CLASS_INVALID << IOPRIO_CLASS_SHIFT; |
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| 117 | |
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| 118 | return (prioclass << IOPRIO_CLASS_SHIFT) | |
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| 119 | (priohint << IOPRIO_HINT_SHIFT) | priolevel; |
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| 120 | } |
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| 121 | |
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| 122 | #define IOPRIO_PRIO_VALUE(prioclass, priolevel) \ |
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| 123 | ioprio_value(prioclass, priolevel, IOPRIO_HINT_NONE) |
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| 124 | #define IOPRIO_PRIO_VALUE_HINT(prioclass, priolevel, priohint) \ |
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| 125 | ioprio_value(prioclass, priolevel, priohint) |
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| 126 | |
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| 127 | #endif /* _UAPI_LINUX_IOPRIO_H */ |
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| 128 | |
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