fs: limit filesystem stacking depth

[pandora-kernel.git] / include / linux / preempt.h

diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 2e681d9..e86bf01 100644 (file)
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -27,6 +27,21 @@
 
 asmlinkage void preempt_schedule(void);
 
+#define preempt_check_resched() \
+do { \
+       if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
+               preempt_schedule(); \
+} while (0)
+
+#else /* !CONFIG_PREEMPT */
+
+#define preempt_check_resched()                do { } while (0)
+
+#endif /* CONFIG_PREEMPT */
+
+
+#ifdef CONFIG_PREEMPT_COUNT
+
 #define preempt_disable() \
 do { \
        inc_preempt_count(); \
@@ -39,12 +54,6 @@ do { \
        dec_preempt_count(); \
 } while (0)
 
-#define preempt_check_resched() \
-do { \
-       if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) \
-               preempt_schedule(); \
-} while (0)
-
 #define preempt_enable() \
 do { \
        preempt_enable_no_resched(); \
@@ -80,18 +89,23 @@ do { \
        preempt_check_resched(); \
 } while (0)
 
-#else
+#else /* !CONFIG_PREEMPT_COUNT */
 
-#define preempt_disable()              do { } while (0)
-#define preempt_enable_no_resched()    do { } while (0)
-#define preempt_enable()               do { } while (0)
-#define preempt_check_resched()                do { } while (0)
+/*
+ * Even if we don't have any preemption, we need preempt disable/enable
+ * to be barriers, so that we don't have things like get_user/put_user
+ * that can cause faults and scheduling migrate into our preempt-protected
+ * region.
+ */
+#define preempt_disable()              barrier()
+#define preempt_enable_no_resched()    barrier()
+#define preempt_enable()               barrier()
 
-#define preempt_disable_notrace()              do { } while (0)
-#define preempt_enable_no_resched_notrace()    do { } while (0)
-#define preempt_enable_notrace()               do { } while (0)
+#define preempt_disable_notrace()              barrier()
+#define preempt_enable_no_resched_notrace()    barrier()
+#define preempt_enable_notrace()               barrier()
 
-#endif
+#endif /* CONFIG_PREEMPT_COUNT */
 
 #ifdef CONFIG_PREEMPT_NOTIFIERS