[PATCH] BLOCK: Remove duplicate declaration of exit_io_context() [try #6]

[karo-tx-linux.git] / kernel / sched.c

diff --git a/kernel/sched.c b/kernel/sched.c
index 5c848fd4e461c67bded9c27b81405889a80cd656..74f169ac0773cd2ac3eeac0bfbb3c3a631d70c65 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1755,27 +1755,27 @@ static inline void finish_task_switch(struct rq *rq, struct task_struct *prev)
        __releases(rq->lock)
 {
        struct mm_struct *mm = rq->prev_mm;
-       unsigned long prev_task_flags;
+       long prev_state;
 
        rq->prev_mm = NULL;
 
        /*
         * A task struct has one reference for the use as "current".
-        * If a task dies, then it sets EXIT_ZOMBIE in tsk->exit_state and
-        * calls schedule one last time. The schedule call will never return,
-        * and the scheduled task must drop that reference.
-        * The test for EXIT_ZOMBIE must occur while the runqueue locks are
+        * If a task dies, then it sets TASK_DEAD in tsk->state and calls
+        * schedule one last time. The schedule call will never return, and
+        * the scheduled task must drop that reference.
+        * The test for TASK_DEAD must occur while the runqueue locks are
         * still held, otherwise prev could be scheduled on another cpu, die
         * there before we look at prev->state, and then the reference would
         * be dropped twice.
         *              Manfred Spraul <manfred@colorfullife.com>
         */
-       prev_task_flags = prev->flags;
+       prev_state = prev->state;
        finish_arch_switch(prev);
        finish_lock_switch(rq, prev);
        if (mm)
                mmdrop(mm);
-       if (unlikely(prev_task_flags & PF_DEAD)) {
+       if (unlikely(prev_state == TASK_DEAD)) {
                /*
                 * Remove function-return probe instances associated with this
                 * task and put them back on the free list.
@@ -3348,9 +3348,6 @@ need_resched_nonpreemptible:
 
        spin_lock_irq(&rq->lock);
 
-       if (unlikely(prev->flags & PF_DEAD))
-               prev->state = EXIT_DEAD;
-
        switch_count = &prev->nivcsw;
        if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
                switch_count = &prev->nvcsw;
@@ -4080,6 +4077,8 @@ static void __setscheduler(struct task_struct *p, int policy, int prio)
  * @p: the task in question.
  * @policy: new policy.
  * @param: structure containing the new RT priority.
+ *
+ * NOTE: the task may be already dead
  */
 int sched_setscheduler(struct task_struct *p, int policy,
                       struct sched_param *param)
@@ -4107,28 +4106,32 @@ recheck:
            (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
            (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
                return -EINVAL;
-       if ((policy == SCHED_NORMAL || policy == SCHED_BATCH)
-                                       != (param->sched_priority == 0))
+       if (is_rt_policy(policy) != (param->sched_priority != 0))
                return -EINVAL;
 
        /*
         * Allow unprivileged RT tasks to decrease priority:
         */
        if (!capable(CAP_SYS_NICE)) {
-               /*
-                * can't change policy, except between SCHED_NORMAL
-                * and SCHED_BATCH:
-                */
-               if (((policy != SCHED_NORMAL && p->policy != SCHED_BATCH) &&
-                       (policy != SCHED_BATCH && p->policy != SCHED_NORMAL)) &&
-                               !p->signal->rlim[RLIMIT_RTPRIO].rlim_cur)
-                       return -EPERM;
-               /* can't increase priority */
-               if ((policy != SCHED_NORMAL && policy != SCHED_BATCH) &&
-                   param->sched_priority > p->rt_priority &&
-                   param->sched_priority >
-                               p->signal->rlim[RLIMIT_RTPRIO].rlim_cur)
-                       return -EPERM;
+               if (is_rt_policy(policy)) {
+                       unsigned long rlim_rtprio;
+                       unsigned long flags;
+
+                       if (!lock_task_sighand(p, &flags))
+                               return -ESRCH;
+                       rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
+                       unlock_task_sighand(p, &flags);
+
+                       /* can't set/change the rt policy */
+                       if (policy != p->policy && !rlim_rtprio)
+                               return -EPERM;
+
+                       /* can't increase priority */
+                       if (param->sched_priority > p->rt_priority &&
+                           param->sched_priority > rlim_rtprio)
+                               return -EPERM;
+               }
+
                /* can't change other user's priorities */
                if ((current->euid != p->euid) &&
                    (current->euid != p->uid))
@@ -4193,14 +4196,13 @@ do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
                return -EINVAL;
        if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
                return -EFAULT;
-       read_lock_irq(&tasklist_lock);
+
+       rcu_read_lock();
+       retval = -ESRCH;
        p = find_process_by_pid(pid);
-       if (!p) {
-               read_unlock_irq(&tasklist_lock);
-               return -ESRCH;
-       }
-       retval = sched_setscheduler(p, policy, &lparam);
-       read_unlock_irq(&tasklist_lock);
+       if (p != NULL)
+               retval = sched_setscheduler(p, policy, &lparam);
+       rcu_read_unlock();
 
        return retval;
 }
@@ -5151,7 +5153,7 @@ static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
        BUG_ON(p->exit_state != EXIT_ZOMBIE && p->exit_state != EXIT_DEAD);
 
        /* Cannot have done final schedule yet: would have vanished. */
-       BUG_ON(p->flags & PF_DEAD);
+       BUG_ON(p->state == TASK_DEAD);
 
        get_task_struct(p);
 
@@ -5272,9 +5274,11 @@ static struct notifier_block __cpuinitdata migration_notifier = {
 int __init migration_init(void)
 {
        void *cpu = (void *)(long)smp_processor_id();
+       int err;
 
        /* Start one for the boot CPU: */
-       migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
+       err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
+       BUG_ON(err == NOTIFY_BAD);
        migration_call(&migration_notifier, CPU_ONLINE, cpu);
        register_cpu_notifier(&migration_notifier);