/*
* fs/ioprio.c
*
- * Copyright (C) 2004 Jens Axboe <axboe@suse.de>
+ * 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
* See also Documentation/block/ioprio.txt
*
*/
+#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/ioprio.h>
#include <linux/blkdev.h>
+#include <linux/capability.h>
+#include <linux/syscalls.h>
+#include <linux/security.h>
+#include <linux/pid_namespace.h>
-static int set_task_ioprio(struct task_struct *task, int ioprio)
+int set_task_ioprio(struct task_struct *task, int ioprio)
{
+ int err;
struct io_context *ioc;
+ const struct cred *cred = current_cred(), *tcred;
- if (task->uid != current->euid &&
- task->uid != current->uid && !capable(CAP_SYS_NICE))
+ rcu_read_lock();
+ tcred = __task_cred(task);
+ if (tcred->uid != cred->euid &&
+ 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;
task_lock(task);
+ do {
+ ioc = task->io_context;
+ /* see wmb() in current_io_context() */
+ smp_read_barrier_depends();
+ if (ioc)
+ break;
- task->ioprio = ioprio;
+ ioc = alloc_io_context(GFP_ATOMIC, -1);
+ if (!ioc) {
+ err = -ENOMEM;
+ break;
+ }
+ task->io_context = ioc;
+ } while (1);
- ioc = task->io_context;
- if (ioc && ioc->set_ioprio)
- ioc->set_ioprio(ioc, ioprio);
+ if (!err) {
+ ioc->ioprio = ioprio;
+ ioc->ioprio_changed = 1;
+ }
task_unlock(task);
- return 0;
+ return err;
}
+EXPORT_SYMBOL_GPL(set_task_ioprio);
-asmlinkage int sys_ioprio_set(int which, int who, int 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;
int ret;
switch (class) {
break;
case IOPRIO_CLASS_IDLE:
break;
+ case IOPRIO_CLASS_NONE:
+ if (data)
+ return -EINVAL;
+ break;
default:
return -EINVAL;
}
ret = -ESRCH;
- read_lock_irq(&tasklist_lock);
+ rcu_read_lock();
switch (which) {
case IOPRIO_WHO_PROCESS:
if (!who)
p = current;
else
- p = find_task_by_pid(who);
+ p = find_task_by_vpid(who);
if (p)
ret = set_task_ioprio(p, ioprio);
break;
case IOPRIO_WHO_PGRP:
if (!who)
- who = process_group(current);
- do_each_task_pid(who, PIDTYPE_PGID, p) {
+ 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_task_pid(who, PIDTYPE_PGID, p);
+ } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
break;
case IOPRIO_WHO_USER:
if (!who)
- user = current->user;
+ user = current_user();
else
user = find_user(who);
break;
do_each_thread(g, p) {
- if (p->uid != who)
+ if (__task_cred(p)->uid != who)
continue;
ret = set_task_ioprio(p, ioprio);
if (ret)
- break;
+ goto free_uid;
} while_each_thread(g, p);
-
+free_uid:
if (who)
free_uid(user);
break;
ret = -EINVAL;
}
- read_unlock_irq(&tasklist_lock);
+ rcu_read_unlock();
return ret;
}
-asmlinkage int sys_ioprio_get(int which, int who)
+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);
+ if (p->io_context)
+ ret = p->io_context->ioprio;
+out:
+ return ret;
+}
+
+int ioprio_best(unsigned short aprio, unsigned short bprio)
+{
+ unsigned short aclass = IOPRIO_PRIO_CLASS(aprio);
+ unsigned short bclass = IOPRIO_PRIO_CLASS(bprio);
+
+ if (aclass == IOPRIO_CLASS_NONE)
+ aclass = IOPRIO_CLASS_BE;
+ if (bclass == IOPRIO_CLASS_NONE)
+ bclass = IOPRIO_CLASS_BE;
+
+ if (aclass == bclass)
+ return min(aprio, bprio);
+ if (aclass > bclass)
+ return bprio;
+ else
+ return aprio;
+}
+
+SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
{
struct task_struct *g, *p;
struct user_struct *user;
+ struct pid *pgrp;
int ret = -ESRCH;
+ int tmpio;
- read_lock_irq(&tasklist_lock);
+ rcu_read_lock();
switch (which) {
case IOPRIO_WHO_PROCESS:
if (!who)
p = current;
else
- p = find_task_by_pid(who);
+ p = find_task_by_vpid(who);
if (p)
- ret = p->ioprio;
+ ret = get_task_ioprio(p);
break;
case IOPRIO_WHO_PGRP:
if (!who)
- who = process_group(current);
- do_each_task_pid(who, PIDTYPE_PGID, p) {
+ 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 = p->ioprio;
+ ret = tmpio;
else
- ret = ioprio_best(ret, p->ioprio);
- } while_each_task_pid(who, PIDTYPE_PGID, p);
+ ret = ioprio_best(ret, tmpio);
+ } while_each_pid_thread(pgrp, PIDTYPE_PGID, p);
break;
case IOPRIO_WHO_USER:
if (!who)
- user = current->user;
+ user = current_user();
else
user = find_user(who);
break;
do_each_thread(g, p) {
- if (p->uid != user->uid)
+ if (__task_cred(p)->uid != user->uid)
+ continue;
+ tmpio = get_task_ioprio(p);
+ if (tmpio < 0)
continue;
if (ret == -ESRCH)
- ret = p->ioprio;
+ ret = tmpio;
else
- ret = ioprio_best(ret, p->ioprio);
+ ret = ioprio_best(ret, tmpio);
} while_each_thread(g, p);
if (who)
ret = -EINVAL;
}
- read_unlock_irq(&tasklist_lock);
+ rcu_read_unlock();
return ret;
}
-
Code Review / linux-2.6.git / blobdiff