Line data    Source code

       1             : #ifndef IOPRIO_H
       2             : #define IOPRIO_H
       3             : 
       4             : /* This is minimal version of Linux' linux/ioprio.h header file, which
       5             :  * is licensed GPL2 */
       6             : 
       7             : #include <unistd.h>
       8             : #include <sys/syscall.h>
       9             : 
      10             : /*
      11             :  * Gives us 8 prio classes with 13-bits of data for each class
      12             :  */
      13             : #define IOPRIO_BITS             (16)
      14             : #define IOPRIO_CLASS_SHIFT      (13)
      15             : #define IOPRIO_PRIO_MASK        ((1UL << IOPRIO_CLASS_SHIFT) - 1)
      16             : 
      17             : #define IOPRIO_PRIO_CLASS(mask) ((mask) >> IOPRIO_CLASS_SHIFT)
      18             : #define IOPRIO_PRIO_DATA(mask)  ((mask) & IOPRIO_PRIO_MASK)
      19             : #define IOPRIO_PRIO_VALUE(class, data)  (((class) << IOPRIO_CLASS_SHIFT) | data)
      20             : 
      21             : #define ioprio_valid(mask)      (IOPRIO_PRIO_CLASS((mask)) != IOPRIO_CLASS_NONE)
      22             : 
      23             : /*
      24             :  * These are the io priority groups as implemented by CFQ. RT is the realtime
      25             :  * class, it always gets premium service. BE is the best-effort scheduling
      26             :  * class, the default for any process. IDLE is the idle scheduling class, it
      27             :  * is only served when no one else is using the disk.
      28             :  */
      29             : enum {
      30             :         IOPRIO_CLASS_NONE,
      31             :         IOPRIO_CLASS_RT,
      32             :         IOPRIO_CLASS_BE,
      33             :         IOPRIO_CLASS_IDLE,
      34             : };
      35             : 
      36             : /*
      37             :  * 8 best effort priority levels are supported
      38             :  */
      39             : #define IOPRIO_BE_NR    (8)
      40             : 
      41             : enum {
      42             :         IOPRIO_WHO_PROCESS = 1,
      43             :         IOPRIO_WHO_PGRP,
      44             :         IOPRIO_WHO_USER,
      45             : };
      46             : 
      47           0 : static inline int ioprio_set(int which, int who, int ioprio) {
      48           0 :         return syscall(__NR_ioprio_set, which, who, ioprio);
      49             : }
      50             : 
      51           0 : static inline int ioprio_get(int which, int who) {
      52           0 :         return syscall(__NR_ioprio_get, which, who);
      53             : }
      54             : 
      55             : #endif