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  */
  19 static 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  */
  30 static 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  */
  39 static 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  */
  53 static 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  */
  65 extern int ioprio_best(unsigned short aprio, unsigned short bprio);
  66
  67 extern int set_task_ioprio(struct task_struct *task, int ioprio);
  68
  69 #ifdef CONFIG_BLOCK
  70 extern int ioprio_check_cap(int ioprio);
  71 #else
  72 static inline int ioprio_check_cap(int ioprio)
  73 {
  74         return -ENOTBLK;
  75 }
  76 #endif /* CONFIG_BLOCK */
  77
  78 #endif