| 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_NONE, 0) |
| 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(p: 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 (rt_or_dl_task_policy(tsk: task)) |
| 44 | return IOPRIO_CLASS_RT; |
| 45 | else |
| 46 | return IOPRIO_CLASS_BE; |
| 47 | } |
| 48 | |
| 49 | #ifdef CONFIG_BLOCK |
| 50 | /* |
| 51 | * If the task has set an I/O priority, use that. Otherwise, return |
| 52 | * the default I/O priority. |
| 53 | * |
| 54 | * Expected to be called for current task or with task_lock() held to keep |
| 55 | * io_context stable. |
| 56 | */ |
| 57 | static inline int __get_task_ioprio(struct task_struct *p) |
| 58 | { |
| 59 | struct io_context *ioc = p->io_context; |
| 60 | int prio; |
| 61 | |
| 62 | if (!ioc) |
| 63 | return IOPRIO_PRIO_VALUE(task_nice_ioclass(p), |
| 64 | task_nice_ioprio(p)); |
| 65 | |
| 66 | if (p != current) |
| 67 | lockdep_assert_held(&p->alloc_lock); |
| 68 | |
| 69 | prio = ioc->ioprio; |
| 70 | if (IOPRIO_PRIO_CLASS(prio) == IOPRIO_CLASS_NONE) |
| 71 | prio = IOPRIO_PRIO_VALUE(task_nice_ioclass(p), |
| 72 | task_nice_ioprio(p)); |
| 73 | return prio; |
| 74 | } |
| 75 | #else |
| 76 | static inline int __get_task_ioprio(struct task_struct *p) |
| 77 | { |
| 78 | return IOPRIO_DEFAULT; |
| 79 | } |
| 80 | #endif /* CONFIG_BLOCK */ |
| 81 | |
| 82 | static inline int get_current_ioprio(void) |
| 83 | { |
| 84 | return __get_task_ioprio(current); |
| 85 | } |
| 86 | |
| 87 | extern int set_task_ioprio(struct task_struct *task, int ioprio); |
| 88 | |
| 89 | #ifdef CONFIG_BLOCK |
| 90 | extern int ioprio_check_cap(int ioprio); |
| 91 | #else |
| 92 | static inline int ioprio_check_cap(int ioprio) |
| 93 | { |
| 94 | return -ENOTBLK; |
| 95 | } |
| 96 | #endif /* CONFIG_BLOCK */ |
| 97 | |
| 98 | #endif |
| 99 |