Merge 'Linux v3.0' into Litmus

Some notes:
* Litmus^RT scheduling class is the topmost scheduling class
  (above stop_sched_class).
* scheduler_ipi() function (e.g., in smp_reschedule_interrupt())
  may increase IPI latencies.
* Added path into schedule() to quickly re-evaluate scheduling
  decision without becoming preemptive again. This used to be
  a standard path before the removal of BKL.

Conflicts:
	Makefile
	arch/arm/kernel/calls.S
	arch/arm/kernel/smp.c
	arch/x86/include/asm/unistd_32.h
	arch/x86/kernel/smp.c
	arch/x86/kernel/syscall_table_32.S
	include/linux/hrtimer.h
	kernel/printk.c
	kernel/sched.c
	kernel/sched_fair.c

1 files changed, 15 insertions, 1 deletions

diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h
index 8a7d510ffa9c..5edc9014263a 100644
--- a/include/linux/percpu_counter.h
+++ b/include/linux/percpu_counter.h
@@ -75,7 +75,12 @@ static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc)
         barrier();              /* Prevent reloads of fbc->count */
         if (ret >= 0)
                 return ret;
-        return 1;
+        return 0;
+}
+
+static inline int percpu_counter_initialized(struct percpu_counter *fbc)
+{
+        return (fbc->counters != NULL);
 }
 
 #else
@@ -128,6 +133,10 @@ static inline s64 percpu_counter_read(struct percpu_counter *fbc)
         return fbc->count;
 }
 
+/*
+ * percpu_counter is intended to track positive numbers. In the UP case the
+ * number should never be negative.
+ */
 static inline s64 percpu_counter_read_positive(struct percpu_counter *fbc)
 {
         return fbc->count;
@@ -143,6 +152,11 @@ static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
         return percpu_counter_read(fbc);
 }
 
+static inline int percpu_counter_initialized(struct percpu_counter *fbc)
+{
+        return 1;
+}
+
 #endif  /* CONFIG_SMP */
 
 static inline void percpu_counter_inc(struct percpu_counter *fbc)