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1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */2#ifndef _UAPI_LINUX_IOPRIO_H3#define _UAPI_LINUX_IOPRIO_H4 5#include <linux/stddef.h>6#include <linux/types.h>7 8/*9 * Gives us 8 prio classes with 13-bits of data for each class10 */11#define IOPRIO_CLASS_SHIFT 1312#define IOPRIO_NR_CLASSES 813#define IOPRIO_CLASS_MASK (IOPRIO_NR_CLASSES - 1)14#define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1)15 16#define IOPRIO_PRIO_CLASS(ioprio) \17 (((ioprio) >> IOPRIO_CLASS_SHIFT) & IOPRIO_CLASS_MASK)18#define IOPRIO_PRIO_DATA(ioprio) ((ioprio) & IOPRIO_PRIO_MASK)19 20/*21 * These are the io priority classes as implemented by the BFQ and mq-deadline22 * schedulers. RT is the realtime class, it always gets premium service. For23 * ATA disks supporting NCQ IO priority, RT class IOs will be processed using24 * high priority NCQ commands. BE is the best-effort scheduling class, the25 * default for any process. IDLE is the idle scheduling class, it is only26 * served when no one else is using the disk.27 */28enum {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 invalid ioprio value */35 IOPRIO_CLASS_INVALID = 7,36};37 38/*39 * The RT and BE priority classes both support up to 8 priority levels that40 * can be specified using the lower 3-bits of the priority data.41 */42#define IOPRIO_LEVEL_NR_BITS 343#define IOPRIO_NR_LEVELS (1 << IOPRIO_LEVEL_NR_BITS)44#define IOPRIO_LEVEL_MASK (IOPRIO_NR_LEVELS - 1)45#define IOPRIO_PRIO_LEVEL(ioprio) ((ioprio) & IOPRIO_LEVEL_MASK)46 47#define IOPRIO_BE_NR IOPRIO_NR_LEVELS48 49/*50 * Possible values for the "which" argument of the ioprio_get() and51 * ioprio_set() system calls (see "man ioprio_set").52 */53enum {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 463#define IOPRIO_BE_NORM IOPRIO_NORM64 65/*66 * The 10 bits between the priority class and the priority level are used to67 * optionally define I/O hints for any combination of I/O priority class and68 * level. Depending on the kernel configuration, I/O scheduler being used and69 * the target I/O device being used, hints can influence how I/Os are processed70 * without affecting the I/O scheduling ordering defined by the I/O priority71 * class and level.72 */73#define IOPRIO_HINT_SHIFT IOPRIO_LEVEL_NR_BITS74#define IOPRIO_HINT_NR_BITS 1075#define IOPRIO_NR_HINTS (1 << IOPRIO_HINT_NR_BITS)76#define IOPRIO_HINT_MASK (IOPRIO_NR_HINTS - 1)77#define IOPRIO_PRIO_HINT(ioprio) \78 (((ioprio) >> IOPRIO_HINT_SHIFT) & IOPRIO_HINT_MASK)79 80/*81 * I/O hints.82 */83enum {84 /* No hint */85 IOPRIO_HINT_NONE = 0,86 87 /*88 * Device command duration limits: indicate to the device a desired89 * duration limit for the commands that will be used to process an I/O.90 * These will currently only be effective for SCSI and ATA devices that91 * support the command duration limits feature. If this feature is92 * enabled, then the commands issued to the device to process an I/O with93 * one of these hints set will have the duration limit index (dld field)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 || (val) >= (max))106 107/*108 * Return an I/O priority value based on a class, a level and a hint.109 */110static __always_inline __u16 ioprio_value(int prioclass, int priolevel,111 int priohint)112{113 if (IOPRIO_BAD_VALUE(prioclass, IOPRIO_NR_CLASSES) ||114 IOPRIO_BAD_VALUE(priolevel, IOPRIO_NR_LEVELS) ||115 IOPRIO_BAD_VALUE(priohint, IOPRIO_NR_HINTS))116 return IOPRIO_CLASS_INVALID << IOPRIO_CLASS_SHIFT;117 118 return (prioclass << IOPRIO_CLASS_SHIFT) |119 (priohint << IOPRIO_HINT_SHIFT) | priolevel;120}121 122#define IOPRIO_PRIO_VALUE(prioclass, priolevel) \123 ioprio_value(prioclass, priolevel, IOPRIO_HINT_NONE)124#define IOPRIO_PRIO_VALUE_HINT(prioclass, priolevel, priohint) \125 ioprio_value(prioclass, priolevel, priohint)126 127#endif /* _UAPI_LINUX_IOPRIO_H */128