Merge to Fedora kernel-2.6.17-1.2187_FC5 patched with stable patch-2.6.17.13-vs2...

[linux-2.6.git] / kernel / sched.c

diff --git a/kernel/sched.c b/kernel/sched.c
index 60bff8b..026ba1f 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4189,17 +4189,22 @@ asmlinkage long sys_sched_yield(void)
        return 0;
 }
 
-static inline void __cond_resched(void)
+static inline int __resched_legal(int expected_preempt_count)
+{
+       if (unlikely(preempt_count() != expected_preempt_count))
+               return 0;
+       if (unlikely(system_state != SYSTEM_RUNNING))
+               return 0;
+       return 1;
+}
+
+static void __cond_resched(void)
 {
        /*
         * The BKS might be reacquired before we have dropped
         * PREEMPT_ACTIVE, which could trigger a second
         * cond_resched() call.
         */
-       if (unlikely(preempt_count()))
-               return;
-       if (unlikely(system_state != SYSTEM_RUNNING))
-               return;
        do {
                add_preempt_count(PREEMPT_ACTIVE);
                schedule();
@@ -4209,13 +4214,12 @@ static inline void __cond_resched(void)
 
 int __sched cond_resched(void)
 {
-       if (need_resched()) {
+       if (need_resched() && __resched_legal(0)) {
                __cond_resched();
                return 1;
        }
        return 0;
 }
-
 EXPORT_SYMBOL(cond_resched);
 
 /*
@@ -4236,7 +4240,7 @@ int cond_resched_lock(spinlock_t *lock)
                ret = 1;
                spin_lock(lock);
        }
-       if (need_resched()) {
+       if (need_resched() && __resched_legal(1)) {
                _raw_spin_unlock(lock);
                preempt_enable_no_resched();
                __cond_resched();
@@ -4245,14 +4249,13 @@ int cond_resched_lock(spinlock_t *lock)
        }
        return ret;
 }
-
 EXPORT_SYMBOL(cond_resched_lock);
 
 int __sched cond_resched_softirq(void)
 {
        BUG_ON(!in_softirq());
 
-       if (need_resched()) {
+       if (need_resched() && __resched_legal(0)) {
                __local_bh_enable();
                __cond_resched();
                local_bh_disable();
@@ -4260,10 +4263,8 @@ int __sched cond_resched_softirq(void)
        }
        return 0;
 }
-
 EXPORT_SYMBOL(cond_resched_softirq);
 
-
 /**
  * yield - yield the current processor to other threads.
  *