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 (task_is_realtime(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_DEFAULT; |
64 | |
65 | if (p != current) |
66 | lockdep_assert_held(&p->alloc_lock); |
67 | |
68 | prio = ioc->ioprio; |
69 | if (IOPRIO_PRIO_CLASS(prio) == IOPRIO_CLASS_NONE) |
70 | prio = IOPRIO_PRIO_VALUE(task_nice_ioclass(p), |
71 | task_nice_ioprio(p)); |
72 | return prio; |
73 | } |
74 | #else |
75 | static inline int __get_task_ioprio(struct task_struct *p) |
76 | { |
77 | return IOPRIO_DEFAULT; |
78 | } |
79 | #endif /* CONFIG_BLOCK */ |
80 | |
81 | static inline int get_current_ioprio(void) |
82 | { |
83 | return __get_task_ioprio(current); |
84 | } |
85 | |
86 | extern int set_task_ioprio(struct task_struct *task, int ioprio); |
87 | |
88 | #ifdef CONFIG_BLOCK |
89 | extern int ioprio_check_cap(int ioprio); |
90 | #else |
91 | static inline int ioprio_check_cap(int ioprio) |
92 | { |
93 | return -ENOTBLK; |
94 | } |
95 | #endif /* CONFIG_BLOCK */ |
96 | |
97 | #endif |
98 |