Viewing file:  ioprio.h (2.11 KB) -rw-r--r--
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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef IOPRIO_H
#define IOPRIO_H
#include <linux/sched.h>
#include <linux/sched/rt.h>
#include <linux/iocontext.h>
#include <uapi/linux/ioprio.h>
/*
* Default IO priority.
*/
#define IOPRIO_DEFAULT IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0)
/*
* Check that a priority value has a valid class.
*/
static inline bool ioprio_valid(unsigned short ioprio)
{
unsigned short class = IOPRIO_PRIO_CLASS(ioprio);
return class > IOPRIO_CLASS_NONE && class <= IOPRIO_CLASS_IDLE;
}
/*
* if process has set io priority explicitly, use that. if not, convert
* the cpu scheduler nice value to an io priority
*/
static inline int task_nice_ioprio(struct task_struct *task)
{
return (task_nice(task) + 20) / 5;
}
/*
* This is for the case where the task hasn't asked for a specific IO class.
* Check for idle and rt task process, and return appropriate IO class.
*/
static inline int task_nice_ioclass(struct task_struct *task)
{
if (task->policy == SCHED_IDLE)
return IOPRIO_CLASS_IDLE;
else if (task_is_realtime(task))
return IOPRIO_CLASS_RT;
else
return IOPRIO_CLASS_BE;
}
#ifdef CONFIG_BLOCK
/*
* If the task has set an I/O priority, use that. Otherwise, return
* the default I/O priority.
*
* Expected to be called for current task or with task_lock() held to keep
* io_context stable.
*/
static inline int __get_task_ioprio(struct task_struct *p)
{
struct io_context *ioc = p->io_context;
int prio;
if (!ioc)
return IOPRIO_DEFAULT;
if (p != current)
lockdep_assert_held(&p->alloc_lock);
prio = ioc->ioprio;
if (IOPRIO_PRIO_CLASS(prio) == IOPRIO_CLASS_NONE)
prio = IOPRIO_PRIO_VALUE(task_nice_ioclass(p),
task_nice_ioprio(p));
return prio;
}
#else
static inline int __get_task_ioprio(struct task_struct *p)
{
return IOPRIO_DEFAULT;
}
#endif /* CONFIG_BLOCK */
static inline int get_current_ioprio(void)
{
return __get_task_ioprio(current);
}
extern int set_task_ioprio(struct task_struct *task, int ioprio);
#ifdef CONFIG_BLOCK
extern int ioprio_check_cap(int ioprio);
#else
static inline int ioprio_check_cap(int ioprio)
{
return -ENOTBLK;
}
#endif /* CONFIG_BLOCK */
#endif
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