提交 948769a5 编写于 作者: L Linus Torvalds

Merge branch 'sched/new-API-sched_setscheduler' of...

Merge branch 'sched/new-API-sched_setscheduler' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'sched/new-API-sched_setscheduler' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: add new API sched_setscheduler_nocheck: add a flag to control access checks
......@@ -1658,6 +1658,8 @@ extern int can_nice(const struct task_struct *p, const int nice);
extern int task_curr(const struct task_struct *p);
extern int idle_cpu(int cpu);
extern int sched_setscheduler(struct task_struct *, int, struct sched_param *);
extern int sched_setscheduler_nocheck(struct task_struct *, int,
struct sched_param *);
extern struct task_struct *idle_task(int cpu);
extern struct task_struct *curr_task(int cpu);
extern void set_curr_task(int cpu, struct task_struct *p);
......
......@@ -4995,16 +4995,8 @@ __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
set_load_weight(p);
}
/**
* sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
* @p: the task in question.
* @policy: new policy.
* @param: structure containing the new RT priority.
*
* NOTE that the task may be already dead.
*/
int sched_setscheduler(struct task_struct *p, int policy,
struct sched_param *param)
static int __sched_setscheduler(struct task_struct *p, int policy,
struct sched_param *param, bool user)
{
int retval, oldprio, oldpolicy = -1, on_rq, running;
unsigned long flags;
......@@ -5036,7 +5028,7 @@ int sched_setscheduler(struct task_struct *p, int policy,
/*
* Allow unprivileged RT tasks to decrease priority:
*/
if (!capable(CAP_SYS_NICE)) {
if (user && !capable(CAP_SYS_NICE)) {
if (rt_policy(policy)) {
unsigned long rlim_rtprio;
......@@ -5072,7 +5064,8 @@ int sched_setscheduler(struct task_struct *p, int policy,
* Do not allow realtime tasks into groups that have no runtime
* assigned.
*/
if (rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0)
if (user
&& rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0)
return -EPERM;
#endif
......@@ -5121,8 +5114,39 @@ int sched_setscheduler(struct task_struct *p, int policy,
return 0;
}
/**
* sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
* @p: the task in question.
* @policy: new policy.
* @param: structure containing the new RT priority.
*
* NOTE that the task may be already dead.
*/
int sched_setscheduler(struct task_struct *p, int policy,
struct sched_param *param)
{
return __sched_setscheduler(p, policy, param, true);
}
EXPORT_SYMBOL_GPL(sched_setscheduler);
/**
* sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
* @p: the task in question.
* @policy: new policy.
* @param: structure containing the new RT priority.
*
* Just like sched_setscheduler, only don't bother checking if the
* current context has permission. For example, this is needed in
* stop_machine(): we create temporary high priority worker threads,
* but our caller might not have that capability.
*/
int sched_setscheduler_nocheck(struct task_struct *p, int policy,
struct sched_param *param)
{
return __sched_setscheduler(p, policy, param, false);
}
static int
do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
{
......
......@@ -645,7 +645,7 @@ static int __cpuinit cpu_callback(struct notifier_block *nfb,
p = per_cpu(ksoftirqd, hotcpu);
per_cpu(ksoftirqd, hotcpu) = NULL;
sched_setscheduler(p, SCHED_FIFO, &param);
sched_setscheduler_nocheck(p, SCHED_FIFO, &param);
kthread_stop(p);
takeover_tasklets(hotcpu);
break;
......
......@@ -187,7 +187,7 @@ struct task_struct *__stop_machine_run(int (*fn)(void *), void *data,
struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 };
/* One high-prio thread per cpu. We'll do this one. */
sched_setscheduler(p, SCHED_FIFO, &param);
sched_setscheduler_nocheck(p, SCHED_FIFO, &param);
kthread_bind(p, cpu);
wake_up_process(p);
wait_for_completion(&smdata.done);
......
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