106447ae5SOliver Hartkopp /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
206447ae5SOliver Hartkopp #ifndef _UAPI_LINUX_IOPRIO_H
306447ae5SOliver Hartkopp #define _UAPI_LINUX_IOPRIO_H
406447ae5SOliver Hartkopp
501584c1eSDamien Le Moal #include <linux/stddef.h>
601584c1eSDamien Le Moal #include <linux/types.h>
701584c1eSDamien Le Moal
806447ae5SOliver Hartkopp /*
906447ae5SOliver Hartkopp * Gives us 8 prio classes with 13-bits of data for each class
1006447ae5SOliver Hartkopp */
11ba05200fSDamien Le Moal #define IOPRIO_CLASS_SHIFT 13
1201584c1eSDamien Le Moal #define IOPRIO_NR_CLASSES 8
1301584c1eSDamien Le Moal #define IOPRIO_CLASS_MASK (IOPRIO_NR_CLASSES - 1)
1406447ae5SOliver Hartkopp #define IOPRIO_PRIO_MASK ((1UL << IOPRIO_CLASS_SHIFT) - 1)
1506447ae5SOliver Hartkopp
16ba05200fSDamien Le Moal #define IOPRIO_PRIO_CLASS(ioprio) \
17ba05200fSDamien Le Moal (((ioprio) >> IOPRIO_CLASS_SHIFT) & IOPRIO_CLASS_MASK)
18ba05200fSDamien Le Moal #define IOPRIO_PRIO_DATA(ioprio) ((ioprio) & IOPRIO_PRIO_MASK)
1906447ae5SOliver Hartkopp
2006447ae5SOliver Hartkopp /*
21eca20409SDamien Le Moal * These are the io priority classes as implemented by the BFQ and mq-deadline
2225bca50eSDamien Le Moal * schedulers. RT is the realtime class, it always gets premium service. For
2325bca50eSDamien Le Moal * ATA disks supporting NCQ IO priority, RT class IOs will be processed using
2425bca50eSDamien Le Moal * high priority NCQ commands. BE is the best-effort scheduling class, the
2525bca50eSDamien Le Moal * default for any process. IDLE is the idle scheduling class, it is only
2625bca50eSDamien Le Moal * served when no one else is using the disk.
2706447ae5SOliver Hartkopp */
2806447ae5SOliver Hartkopp enum {
2901584c1eSDamien Le Moal IOPRIO_CLASS_NONE = 0,
3001584c1eSDamien Le Moal IOPRIO_CLASS_RT = 1,
3101584c1eSDamien Le Moal IOPRIO_CLASS_BE = 2,
3201584c1eSDamien Le Moal IOPRIO_CLASS_IDLE = 3,
3301584c1eSDamien Le Moal
3401584c1eSDamien Le Moal /* Special class to indicate an invalid ioprio value */
3501584c1eSDamien Le Moal IOPRIO_CLASS_INVALID = 7,
3606447ae5SOliver Hartkopp };
3706447ae5SOliver Hartkopp
3806447ae5SOliver Hartkopp /*
39eca20409SDamien Le Moal * The RT and BE priority classes both support up to 8 priority levels that
40eca20409SDamien Le Moal * can be specified using the lower 3-bits of the priority data.
4106447ae5SOliver Hartkopp */
42eca20409SDamien Le Moal #define IOPRIO_LEVEL_NR_BITS 3
43eca20409SDamien Le Moal #define IOPRIO_NR_LEVELS (1 << IOPRIO_LEVEL_NR_BITS)
44eca20409SDamien Le Moal #define IOPRIO_LEVEL_MASK (IOPRIO_NR_LEVELS - 1)
45eca20409SDamien Le Moal #define IOPRIO_PRIO_LEVEL(ioprio) ((ioprio) & IOPRIO_LEVEL_MASK)
46eca20409SDamien Le Moal
47202bc942SDamien Le Moal #define IOPRIO_BE_NR IOPRIO_NR_LEVELS
4806447ae5SOliver Hartkopp
49eca20409SDamien Le Moal /*
50eca20409SDamien Le Moal * Possible values for the "which" argument of the ioprio_get() and
51eca20409SDamien Le Moal * ioprio_set() system calls (see "man ioprio_set").
52eca20409SDamien Le Moal */
5306447ae5SOliver Hartkopp enum {
5406447ae5SOliver Hartkopp IOPRIO_WHO_PROCESS = 1,
5506447ae5SOliver Hartkopp IOPRIO_WHO_PGRP,
5606447ae5SOliver Hartkopp IOPRIO_WHO_USER,
5706447ae5SOliver Hartkopp };
5806447ae5SOliver Hartkopp
5906447ae5SOliver Hartkopp /*
60eca20409SDamien Le Moal * Fallback BE class priority level.
6106447ae5SOliver Hartkopp */
62e70344c0SDamien Le Moal #define IOPRIO_NORM 4
63e70344c0SDamien Le Moal #define IOPRIO_BE_NORM IOPRIO_NORM
6406447ae5SOliver Hartkopp
656c913257SDamien Le Moal /*
666c913257SDamien Le Moal * The 10 bits between the priority class and the priority level are used to
676c913257SDamien Le Moal * optionally define I/O hints for any combination of I/O priority class and
686c913257SDamien Le Moal * level. Depending on the kernel configuration, I/O scheduler being used and
696c913257SDamien Le Moal * the target I/O device being used, hints can influence how I/Os are processed
706c913257SDamien Le Moal * without affecting the I/O scheduling ordering defined by the I/O priority
716c913257SDamien Le Moal * class and level.
726c913257SDamien Le Moal */
736c913257SDamien Le Moal #define IOPRIO_HINT_SHIFT IOPRIO_LEVEL_NR_BITS
746c913257SDamien Le Moal #define IOPRIO_HINT_NR_BITS 10
756c913257SDamien Le Moal #define IOPRIO_NR_HINTS (1 << IOPRIO_HINT_NR_BITS)
766c913257SDamien Le Moal #define IOPRIO_HINT_MASK (IOPRIO_NR_HINTS - 1)
776c913257SDamien Le Moal #define IOPRIO_PRIO_HINT(ioprio) \
786c913257SDamien Le Moal (((ioprio) >> IOPRIO_HINT_SHIFT) & IOPRIO_HINT_MASK)
796c913257SDamien Le Moal
806c913257SDamien Le Moal /*
816c913257SDamien Le Moal * I/O hints.
826c913257SDamien Le Moal */
836c913257SDamien Le Moal enum {
846c913257SDamien Le Moal /* No hint */
856c913257SDamien Le Moal IOPRIO_HINT_NONE = 0,
866c913257SDamien Le Moal
876c913257SDamien Le Moal /*
886c913257SDamien Le Moal * Device command duration limits: indicate to the device a desired
896c913257SDamien Le Moal * duration limit for the commands that will be used to process an I/O.
906c913257SDamien Le Moal * These will currently only be effective for SCSI and ATA devices that
916c913257SDamien Le Moal * support the command duration limits feature. If this feature is
926c913257SDamien Le Moal * enabled, then the commands issued to the device to process an I/O with
936c913257SDamien Le Moal * one of these hints set will have the duration limit index (dld field)
946c913257SDamien Le Moal * set to the value of the hint.
956c913257SDamien Le Moal */
966c913257SDamien Le Moal IOPRIO_HINT_DEV_DURATION_LIMIT_1 = 1,
976c913257SDamien Le Moal IOPRIO_HINT_DEV_DURATION_LIMIT_2 = 2,
986c913257SDamien Le Moal IOPRIO_HINT_DEV_DURATION_LIMIT_3 = 3,
996c913257SDamien Le Moal IOPRIO_HINT_DEV_DURATION_LIMIT_4 = 4,
1006c913257SDamien Le Moal IOPRIO_HINT_DEV_DURATION_LIMIT_5 = 5,
1016c913257SDamien Le Moal IOPRIO_HINT_DEV_DURATION_LIMIT_6 = 6,
1026c913257SDamien Le Moal IOPRIO_HINT_DEV_DURATION_LIMIT_7 = 7,
1036c913257SDamien Le Moal };
1046c913257SDamien Le Moal
10501584c1eSDamien Le Moal #define IOPRIO_BAD_VALUE(val, max) ((val) < 0 || (val) >= (max))
10601584c1eSDamien Le Moal
10701584c1eSDamien Le Moal /*
10801584c1eSDamien Le Moal * Return an I/O priority value based on a class, a level and a hint.
10901584c1eSDamien Le Moal */
ioprio_value(int prioclass,int priolevel,int priohint)110*c7b4b23bSDamien Le Moal static __always_inline __u16 ioprio_value(int prioclass, int priolevel,
111*c7b4b23bSDamien Le Moal int priohint)
11201584c1eSDamien Le Moal {
113*c7b4b23bSDamien Le Moal if (IOPRIO_BAD_VALUE(prioclass, IOPRIO_NR_CLASSES) ||
114*c7b4b23bSDamien Le Moal IOPRIO_BAD_VALUE(priolevel, IOPRIO_NR_LEVELS) ||
115*c7b4b23bSDamien Le Moal IOPRIO_BAD_VALUE(priohint, IOPRIO_NR_HINTS))
11601584c1eSDamien Le Moal return IOPRIO_CLASS_INVALID << IOPRIO_CLASS_SHIFT;
11701584c1eSDamien Le Moal
118*c7b4b23bSDamien Le Moal return (prioclass << IOPRIO_CLASS_SHIFT) |
119*c7b4b23bSDamien Le Moal (priohint << IOPRIO_HINT_SHIFT) | priolevel;
12001584c1eSDamien Le Moal }
12101584c1eSDamien Le Moal
122*c7b4b23bSDamien Le Moal #define IOPRIO_PRIO_VALUE(prioclass, priolevel) \
123*c7b4b23bSDamien Le Moal ioprio_value(prioclass, priolevel, IOPRIO_HINT_NONE)
124*c7b4b23bSDamien Le Moal #define IOPRIO_PRIO_VALUE_HINT(prioclass, priolevel, priohint) \
125*c7b4b23bSDamien Le Moal ioprio_value(prioclass, priolevel, priohint)
12601584c1eSDamien Le Moal
12706447ae5SOliver Hartkopp #endif /* _UAPI_LINUX_IOPRIO_H */
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