LXR linux/include/linux/ioprio.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef IOPRIO_H
   3#define IOPRIO_H
   4
   5#include <linux/sched.h>
   6#include <linux/sched/rt.h>
   7#include <linux/iocontext.h>
   8
   9#include <uapi/linux/ioprio.h>
  10
  11/*
  12 * Default IO priority.
  13 */
  14#define IOPRIO_DEFAULT  IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_BE_NORM)
  15
  16/*
  17 * Check that a priority value has a valid class.
  18 */
  19static inline bool ioprio_valid(unsigned short ioprio)
  20{
  21        unsigned short class = IOPRIO_PRIO_CLASS(ioprio);
  22
  23        return class > IOPRIO_CLASS_NONE && class <= IOPRIO_CLASS_IDLE;
  24}
  25
  26/*
  27 * if process has set io priority explicitly, use that. if not, convert
  28 * the cpu scheduler nice value to an io priority
  29 */
  30static inline int task_nice_ioprio(struct task_struct *task)
  31{
  32        return (task_nice(task) + 20) / 5;
  33}
  34
  35/*
  36 * This is for the case where the task hasn't asked for a specific IO class.
  37 * Check for idle and rt task process, and return appropriate IO class.
  38 */
  39static inline int task_nice_ioclass(struct task_struct *task)
  40{
  41        if (task->policy == SCHED_IDLE)
  42                return IOPRIO_CLASS_IDLE;
  43        else if (task_is_realtime(task))
  44                return IOPRIO_CLASS_RT;
  45        else
  46                return IOPRIO_CLASS_BE;
  47}
  48
  49/*
  50 * If the calling process has set an I/O priority, use that. Otherwise, return
  51 * the default I/O priority.
  52 */
  53static inline int get_current_ioprio(void)
  54{
  55        struct io_context *ioc = current->io_context;
  56
  57        if (ioc)
  58                return ioc->ioprio;
  59        return IOPRIO_DEFAULT;
  60}
  61
  62/*
  63 * For inheritance, return the highest of the two given priorities
  64 */
  65extern int ioprio_best(unsigned short aprio, unsigned short bprio);
  66
  67extern int set_task_ioprio(struct task_struct *task, int ioprio);
  68
  69#ifdef CONFIG_BLOCK
  70extern int ioprio_check_cap(int ioprio);
  71#else
  72static inline int ioprio_check_cap(int ioprio)
  73{
  74        return -ENOTBLK;
  75}
  76#endif /* CONFIG_BLOCK */
  77
  78#endif
  79