1 files changed, 30 insertions, 83 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 13049aac05a6..f0f831e8a345 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -307,66 +307,6 @@ __read_mostly int scheduler_running;
 int sysctl_sched_rt_runtime = 950000;
 
 /*
- * __task_rq_lock - lock the rq @p resides on.
- */
-static inline struct rq *__task_rq_lock(struct task_struct *p)
-        __acquires(rq->lock)
-{
-        struct rq *rq;
-
-        lockdep_assert_held(&p->pi_lock);
-
-        for (;;) {
-                rq = task_rq(p);
-                raw_spin_lock(&rq->lock);
-                if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
-                        return rq;
-                raw_spin_unlock(&rq->lock);
-
-                while (unlikely(task_on_rq_migrating(p)))
-                        cpu_relax();
-        }
-}
-
-/*
- * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
- */
-static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
-        __acquires(p->pi_lock)
-        __acquires(rq->lock)
-{
-        struct rq *rq;
-
-        for (;;) {
-                raw_spin_lock_irqsave(&p->pi_lock, *flags);
-                rq = task_rq(p);
-                raw_spin_lock(&rq->lock);
-                if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
-                        return rq;
-                raw_spin_unlock(&rq->lock);
-                raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
-
-                while (unlikely(task_on_rq_migrating(p)))
-                        cpu_relax();
-        }
-}
-
-static void __task_rq_unlock(struct rq *rq)
-        __releases(rq->lock)
-{
-        raw_spin_unlock(&rq->lock);
-}
-
-static inline void
-task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags)
-        __releases(rq->lock)
-        __releases(p->pi_lock)
-{
-        raw_spin_unlock(&rq->lock);
-        raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
-}
-
-/*
  * this_rq_lock - lock this runqueue and disable interrupts.
  */
 static struct rq *this_rq_lock(void)
@@ -2899,7 +2839,7 @@ void __sched schedule_preempt_disabled(void)
         preempt_disable();
 }
 
-static void preempt_schedule_common(void)
+static void __sched notrace preempt_schedule_common(void)
 {
         do {
                 __preempt_count_add(PREEMPT_ACTIVE);
@@ -4418,36 +4358,29 @@ EXPORT_SYMBOL_GPL(yield_to);
  * This task is about to go to sleep on IO. Increment rq->nr_iowait so
  * that process accounting knows that this is a task in IO wait state.
  */
-void __sched io_schedule(void)
-{
-        struct rq *rq = raw_rq();
-
-        delayacct_blkio_start();
-        atomic_inc(&rq->nr_iowait);
-        blk_flush_plug(current);
-        current->in_iowait = 1;
-        schedule();
-        current->in_iowait = 0;
-        atomic_dec(&rq->nr_iowait);
-        delayacct_blkio_end();
-}
-EXPORT_SYMBOL(io_schedule);
-
 long __sched io_schedule_timeout(long timeout)
 {
-        struct rq *rq = raw_rq();
+        int old_iowait = current->in_iowait;
+        struct rq *rq;
         long ret;
 
+        current->in_iowait = 1;
+        if (old_iowait)
+                blk_schedule_flush_plug(current);
+        else
+                blk_flush_plug(current);
+
         delayacct_blkio_start();
+        rq = raw_rq();
         atomic_inc(&rq->nr_iowait);
-        blk_flush_plug(current);
-        current->in_iowait = 1;
         ret = schedule_timeout(timeout);
-        current->in_iowait = 0;
+        current->in_iowait = old_iowait;
         atomic_dec(&rq->nr_iowait);
         delayacct_blkio_end();
+
         return ret;
 }
+EXPORT_SYMBOL(io_schedule_timeout);
 
 /**
  * sys_sched_get_priority_max - return maximum RT priority.
@@ -7642,6 +7575,12 @@ static inline int tg_has_rt_tasks(struct task_group *tg)
 {
         struct task_struct *g, *p;
 
+        /*
+         * Autogroups do not have RT tasks; see autogroup_create().
+         */
+        if (task_group_is_autogroup(tg))
+                return 0;
+
         for_each_process_thread(g, p) {
                 if (rt_task(p) && task_group(p) == tg)
                         return 1;
@@ -7734,6 +7673,17 @@ static int tg_set_rt_bandwidth(struct task_group *tg,
 {
         int i, err = 0;
 
+        /*
+         * Disallowing the root group RT runtime is BAD, it would disallow the
+         * kernel creating (and or operating) RT threads.
+         */
+        if (tg == &root_task_group && rt_runtime == 0)
+                return -EINVAL;
+
+        /* No period doesn't make any sense. */
+        if (rt_period == 0)
+                return -EINVAL;
+
         mutex_lock(&rt_constraints_mutex);
         read_lock(&tasklist_lock);
         err = __rt_schedulable(tg, rt_period, rt_runtime);
@@ -7790,9 +7740,6 @@ static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
         rt_period = (u64)rt_period_us * NSEC_PER_USEC;
         rt_runtime = tg->rt_bandwidth.rt_runtime;
 
-        if (rt_period == 0)
-                return -EINVAL;
-
         return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
 }