#include <linux/blkdev.h>
#include <linux/capability.h>
#include <linux/syscalls.h>
+#include <linux/security.h>
static int set_task_ioprio(struct task_struct *task, int ioprio)
{
+ int err;
struct io_context *ioc;
if (task->uid != current->euid &&
task->uid != current->uid && !capable(CAP_SYS_NICE))
return -EPERM;
+ err = security_task_setioprio(task, ioprio);
+ if (err)
+ return err;
+
task_lock(task);
task->ioprio = ioprio;
ioc = task->io_context;
+ /* see wmb() in current_io_context() */
+ smp_read_barrier_depends();
+
if (ioc && ioc->set_ioprio)
ioc->set_ioprio(ioc, ioprio);
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;
return ret;
}
+static int get_task_ioprio(struct task_struct *p)
+{
+ int ret;
+
+ ret = security_task_getioprio(p);
+ if (ret)
+ goto out;
+ ret = p->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 (!ioprio_valid(aprio))
+ return bprio;
+ if (!ioprio_valid(bprio))
+ return aprio;
+
+ 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;
+}
+
asmlinkage long sys_ioprio_get(int which, int who)
{
struct task_struct *g, *p;
struct user_struct *user;
int ret = -ESRCH;
+ int tmpio;
read_lock_irq(&tasklist_lock);
switch (which) {
else
p = find_task_by_pid(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) {
+ 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_task_pid(who, PIDTYPE_PGID, p);
break;
case IOPRIO_WHO_USER:
do_each_thread(g, p) {
if (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)