Release 4.15 block/ioprio.c
/*
* 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.txt
*
*/
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/ioprio.h>
#include <linux/cred.h>
#include <linux/blkdev.h>
#include <linux/capability.h>
#include <linux/sched/user.h>
#include <linux/sched/task.h>
#include <linux/syscalls.h>
#include <linux/security.h>
#include <linux/pid_namespace.h>
int set_task_ioprio(struct task_struct *task, int ioprio)
{
int err;
struct io_context *ioc;
const struct cred *cred = current_cred(), *tcred;
rcu_read_lock();
tcred = __task_cred(task);
if (!uid_eq(tcred->uid, cred->euid) &&
!uid_eq(tcred->uid, cred->uid) && !capable(CAP_SYS_NICE)) {
rcu_read_unlock();
return -EPERM;
}
rcu_read_unlock();
err = security_task_setioprio(task, ioprio);
if (err)
return err;
ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
if (ioc) {
ioc->ioprio = ioprio;
put_io_context(ioc);
}
return err;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Jens Axboe | 56 | 41.79% | 2 | 25.00% |
David Howells | 39 | 29.10% | 2 | 25.00% |
James Morris | 19 | 14.18% | 1 | 12.50% |
Eric W. Biedermann | 10 | 7.46% | 1 | 12.50% |
Tejun Heo | 10 | 7.46% | 2 | 25.00% |
Total | 134 | 100.00% | 8 | 100.00% |
EXPORT_SYMBOL_GPL(set_task_ioprio);
SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
{
int class = IOPRIO_PRIO_CLASS(ioprio);
int data = IOPRIO_PRIO_DATA(ioprio);
struct task_struct *p, *g;
struct user_struct *user;
struct pid *pgrp;
kuid_t uid;
int ret;
switch (class) {
case IOPRIO_CLASS_RT:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
/* fall through */
/* rt has prio field too */
case IOPRIO_CLASS_BE:
if (data >= IOPRIO_BE_NR || data < 0)
return -EINVAL;
break;
case IOPRIO_CLASS_IDLE:
break;
case IOPRIO_CLASS_NONE:
if (data)
return -EINVAL;
break;
default:
return -EINVAL;
}
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);
do_each_pid_thread(pgrp, PIDTYPE_PGID, p) {
ret = set_task_ioprio(p, ioprio);
if (ret)
break;
} while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
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;
}
rcu_read_unlock();
return ret;
}
static int get_task_ioprio(struct task_struct *p)
{
int ret;
ret = security_task_getioprio(p);
if (ret)
goto out;
ret = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, IOPRIO_NORM);
task_lock(p);
if (p->io_context)
ret = p->io_context->ioprio;
task_unlock(p);
out:
return ret;
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
David P. Quigley | 39 | 59.09% | 1 | 33.33% |
Jens Axboe | 17 | 25.76% | 1 | 33.33% |
Omar Sandoval | 10 | 15.15% | 1 | 33.33% |
Total | 66 | 100.00% | 3 | 100.00% |
int ioprio_best(unsigned short aprio, unsigned short bprio)
{
if (!ioprio_valid(aprio))
aprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_NORM);
if (!ioprio_valid(bprio))
bprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, IOPRIO_NORM);
return min(aprio, bprio);
}
Contributors
Person | Tokens | Prop | Commits | CommitProp |
Oleg Nesterov | 32 | 58.18% | 1 | 50.00% |
Jan Kara | 23 | 41.82% | 1 | 50.00% |
Total | 55 | 100.00% | 2 | 100.00% |
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_ioprio(p);
break;
case IOPRIO_WHO_PGRP:
if (!who)
pgrp = task_pgrp(current);
else
pgrp = find_vpid(who);
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);
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;
}
Overall Contributors
Person | Tokens | Prop | Commits | CommitProp |
Jens Axboe | 510 | 55.25% | 4 | 11.43% |
Eric W. Biedermann | 102 | 11.05% | 4 | 11.43% |
David P. Quigley | 77 | 8.34% | 1 | 2.86% |
David Howells | 43 | 4.66% | 3 | 8.57% |
Oleg Nesterov | 37 | 4.01% | 2 | 5.71% |
Heiko Carstens | 28 | 3.03% | 1 | 2.86% |
Jan Kara | 23 | 2.49% | 1 | 2.86% |
James Morris | 22 | 2.38% | 1 | 2.86% |
Tejun Heo | 13 | 1.41% | 3 | 8.57% |
Ben Segall | 12 | 1.30% | 1 | 2.86% |
Omar Sandoval | 10 | 1.08% | 1 | 2.86% |
Ingo Molnar | 9 | 0.98% | 3 | 8.57% |
Greg Thelen | 8 | 0.87% | 1 | 2.86% |
Pavel Emelyanov | 7 | 0.76% | 2 | 5.71% |
Theodore Y. Ts'o | 5 | 0.54% | 1 | 2.86% |
Ken Chen | 4 | 0.43% | 1 | 2.86% |
Randy Dunlap | 3 | 0.33% | 1 | 2.86% |
Adrian Bunk | 3 | 0.33% | 1 | 2.86% |
Paul Gortmaker | 3 | 0.33% | 1 | 2.86% |
Tetsuo Handa | 2 | 0.22% | 1 | 2.86% |
Bart Van Assche | 2 | 0.22% | 1 | 2.86% |
Total | 923 | 100.00% | 35 | 100.00% |
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