Contributors: 32
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Jens Axboe |
407 |
43.21% |
3 |
5.66% |
| David P. Quigley |
101 |
10.72% |
1 |
1.89% |
| Jan Kara |
95 |
10.08% |
4 |
7.55% |
| Eric W. Biedermann |
93 |
9.87% |
4 |
7.55% |
| Peter Zijlstra |
37 |
3.93% |
1 |
1.89% |
| Heiko Carstens |
28 |
2.97% |
1 |
1.89% |
| Adam Manzanares |
24 |
2.55% |
1 |
1.89% |
| Damien Le Moal |
21 |
2.23% |
5 |
9.43% |
| Linus Torvalds (pre-git) |
21 |
2.23% |
5 |
9.43% |
| Ben Segall |
12 |
1.27% |
1 |
1.89% |
| Kirill Korotaev |
12 |
1.27% |
1 |
1.89% |
| Omar Sandoval |
10 |
1.06% |
1 |
1.89% |
| Ingo Molnar |
9 |
0.96% |
2 |
3.77% |
| Greg Thelen |
8 |
0.85% |
1 |
1.89% |
| Roland McGrath |
6 |
0.64% |
1 |
1.89% |
| Oleg Nesterov |
6 |
0.64% |
2 |
3.77% |
| Andrew Morton |
6 |
0.64% |
2 |
3.77% |
| Greg Kroah-Hartman |
6 |
0.64% |
1 |
1.89% |
| Daniel Jacobowitz |
6 |
0.64% |
1 |
1.89% |
| Pavel Emelyanov |
4 |
0.42% |
2 |
3.77% |
| Kenneth W Chen |
4 |
0.42% |
1 |
1.89% |
| David Howells |
4 |
0.42% |
1 |
1.89% |
| Randy Dunlap |
3 |
0.32% |
1 |
1.89% |
| Avi Kivity |
3 |
0.32% |
1 |
1.89% |
| Sukadev Bhattiprolu |
3 |
0.32% |
2 |
3.77% |
| Adrian Bunk |
3 |
0.32% |
1 |
1.89% |
| Alistair Delva |
3 |
0.32% |
1 |
1.89% |
| Gustavo A. R. Silva |
2 |
0.21% |
1 |
1.89% |
| Tetsuo Handa |
2 |
0.21% |
1 |
1.89% |
| Bart Van Assche |
1 |
0.11% |
1 |
1.89% |
| Christoph Hellwig |
1 |
0.11% |
1 |
1.89% |
| Mauro Carvalho Chehab |
1 |
0.11% |
1 |
1.89% |
| Total |
942 |
|
53 |
|
// SPDX-License-Identifier: GPL-2.0
/*
* fs/ioprio.c
*
* Copyright (C) 2004 Jens Axboe <axboe@kernel.dk>
*
* Helper functions for setting/querying io priorities of processes. The
* system calls closely mimmick getpriority/setpriority, see the man page for
* those. The prio argument is a composite of prio class and prio data, where
* the data argument has meaning within that class. The standard scheduling
* classes have 8 distinct prio levels, with 0 being the highest prio and 7
* being the lowest.
*
* IOW, setting BE scheduling class with prio 2 is done ala:
*
* unsigned int prio = (IOPRIO_CLASS_BE << IOPRIO_CLASS_SHIFT) | 2;
*
* ioprio_set(PRIO_PROCESS, pid, prio);
*
* See also Documentation/block/ioprio.rst
*
*/
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/ioprio.h>
#include <linux/cred.h>
#include <linux/blkdev.h>
#include <linux/capability.h>
#include <linux/syscalls.h>
#include <linux/security.h>
#include <linux/pid_namespace.h>
int ioprio_check_cap(int ioprio)
{
int class = IOPRIO_PRIO_CLASS(ioprio);
int level = IOPRIO_PRIO_LEVEL(ioprio);
switch (class) {
case IOPRIO_CLASS_RT:
/*
* Originally this only checked for CAP_SYS_ADMIN,
* which was implicitly allowed for pid 0 by security
* modules such as SELinux. Make sure we check
* CAP_SYS_ADMIN first to avoid a denial/avc for
* possibly missing CAP_SYS_NICE permission.
*/
if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_NICE))
return -EPERM;
fallthrough;
/* rt has prio field too */
case IOPRIO_CLASS_BE:
if (level >= IOPRIO_NR_LEVELS)
return -EINVAL;
break;
case IOPRIO_CLASS_IDLE:
break;
case IOPRIO_CLASS_NONE:
if (level)
return -EINVAL;
break;
case IOPRIO_CLASS_INVALID:
default:
return -EINVAL;
}
return 0;
}
SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
{
struct task_struct *p, *g;
struct user_struct *user;
struct pid *pgrp;
kuid_t uid;
int ret;
ret = ioprio_check_cap(ioprio);
if (ret)
return ret;
ret = -ESRCH;
rcu_read_lock();
switch (which) {
case IOPRIO_WHO_PROCESS:
if (!who)
p = current;
else
p = find_task_by_vpid(who);
if (p)
ret = set_task_ioprio(p, ioprio);
break;
case IOPRIO_WHO_PGRP:
if (!who)
pgrp = task_pgrp(current);
else
pgrp = find_vpid(who);
read_lock(&tasklist_lock);
do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
ret = set_task_ioprio(p, ioprio);
if (ret) {
read_unlock(&tasklist_lock);
goto out;
}
} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
read_unlock(&tasklist_lock);
break;
case IOPRIO_WHO_USER:
uid = make_kuid(current_user_ns(), who);
if (!uid_valid(uid))
break;
if (!who)
user = current_user();
else
user = find_user(uid);
if (!user)
break;
for_each_process_thread(g, p) {
if (!uid_eq(task_uid(p), uid) ||
!task_pid_vnr(p))
continue;
ret = set_task_ioprio(p, ioprio);
if (ret)
goto free_uid;
}
free_uid:
if (who)
free_uid(user);
break;
default:
ret = -EINVAL;
}
out:
rcu_read_unlock();
return ret;
}
/*
* 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.
*/
int __get_task_ioprio(struct task_struct *p)
{
struct io_context *ioc = p->io_context;
int prio;
if (p != current)
lockdep_assert_held(&p->alloc_lock);
if (ioc)
prio = ioc->ioprio;
else
prio = IOPRIO_DEFAULT;
if (IOPRIO_PRIO_CLASS(prio) == IOPRIO_CLASS_NONE)
prio = IOPRIO_PRIO_VALUE(task_nice_ioclass(p),
task_nice_ioprio(p));
return prio;
}
EXPORT_SYMBOL_GPL(__get_task_ioprio);
static int get_task_ioprio(struct task_struct *p)
{
int ret;
ret = security_task_getioprio(p);
if (ret)
goto out;
task_lock(p);
ret = __get_task_ioprio(p);
task_unlock(p);
out:
return ret;
}
/*
* Return raw IO priority value as set by userspace. We use this for
* ioprio_get(pid, IOPRIO_WHO_PROCESS) so that we keep historical behavior and
* also so that userspace can distinguish unset IO priority (which just gets
* overriden based on task's nice value) from IO priority set to some value.
*/
static int get_task_raw_ioprio(struct task_struct *p)
{
int ret;
ret = security_task_getioprio(p);
if (ret)
goto out;
task_lock(p);
if (p->io_context)
ret = p->io_context->ioprio;
else
ret = IOPRIO_DEFAULT;
task_unlock(p);
out:
return ret;
}
static int ioprio_best(unsigned short aprio, unsigned short bprio)
{
return min(aprio, bprio);
}
SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
{
struct task_struct *g, *p;
struct user_struct *user;
struct pid *pgrp;
kuid_t uid;
int ret = -ESRCH;
int tmpio;
rcu_read_lock();
switch (which) {
case IOPRIO_WHO_PROCESS:
if (!who)
p = current;
else
p = find_task_by_vpid(who);
if (p)
ret = get_task_raw_ioprio(p);
break;
case IOPRIO_WHO_PGRP:
if (!who)
pgrp = task_pgrp(current);
else
pgrp = find_vpid(who);
read_lock(&tasklist_lock);
do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
tmpio = get_task_ioprio(p);
if (tmpio < 0)
continue;
if (ret == -ESRCH)
ret = tmpio;
else
ret = ioprio_best(ret, tmpio);
} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
read_unlock(&tasklist_lock);
break;
case IOPRIO_WHO_USER:
uid = make_kuid(current_user_ns(), who);
if (!who)
user = current_user();
else
user = find_user(uid);
if (!user)
break;
for_each_process_thread(g, p) {
if (!uid_eq(task_uid(p), user->uid) ||
!task_pid_vnr(p))
continue;
tmpio = get_task_ioprio(p);
if (tmpio < 0)
continue;
if (ret == -ESRCH)
ret = tmpio;
else
ret = ioprio_best(ret, tmpio);
}
if (who)
free_uid(user);
break;
default:
ret = -EINVAL;
}
rcu_read_unlock();
return ret;
}