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