[PATCH] set TASK_RUNNING in cond_resched()

do_select() does set_current_state(TASK_INTERRUPTIBLE) then calls
__pollwait() which calls __get_free_page() and the cond_resched() which
I added to the pagecache reclaim code never returns.

The patch makes cond_resched() more useful by setting current->state to
TASK_RUNNING before scheduling.

include/linux/sched.h

@@ -837,10 +837,11 @@ static inline int need_resched(void)
 	return unlikely(test_thread_flag(TIF_NEED_RESCHED));
 }
 
+extern void __cond_resched(void);
 static inline void cond_resched(void)
 {
 	if (need_resched())
-		schedule();
+		__cond_resched();
 }
 
 /* Reevaluate whether the task has signals pending delivery.

kernel/ksyms.c

@@ -473,6 +473,7 @@ EXPORT_SYMBOL(preempt_schedule);
 #endif
 EXPORT_SYMBOL(schedule_timeout);
 EXPORT_SYMBOL(sys_sched_yield);
+EXPORT_SYMBOL(__cond_resched);
 EXPORT_SYMBOL(set_user_nice);
 EXPORT_SYMBOL(task_nice);
 EXPORT_SYMBOL_GPL(idle_cpu);

kernel/sched.c

@@ -1447,6 +1447,12 @@ asmlinkage long sys_sched_yield(void)
 	return 0;
 }
 
+void __cond_resched(void)
+{
+	set_current_state(TASK_RUNNING);
+	schedule();
+}
+
 asmlinkage long sys_sched_get_priority_max(int policy)
 {
 	int ret = -EINVAL;