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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-04-14 18:21:35 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-04-14 18:21:35 -0700
commit2f093e2aa466d799c0952bfd1c6c68ff5d80fc17 (patch)
treee3d511aca536b7123d256b98a0ef8e74fc219498 /include/linux/preempt.h
parenta7761027656dc192b59617a6eb961e38097419ce (diff)
parent41ef2d5678d83af030125550329b6ae8b74618fa (diff)
downloadlinux-2f093e2aa466d799c0952bfd1c6c68ff5d80fc17.tar.gz
Merge 3.9-rc7 into char-misc-next
We want the fixes in there. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/preempt.h')
-rw-r--r--include/linux/preempt.h22
1 files changed, 14 insertions, 8 deletions
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 5a710b9c578..87a03c746f1 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -93,14 +93,20 @@ do { \
#else /* !CONFIG_PREEMPT_COUNT */
-#define preempt_disable() do { } while (0)
-#define sched_preempt_enable_no_resched() do { } while (0)
-#define preempt_enable_no_resched() do { } while (0)
-#define preempt_enable() do { } while (0)
-
-#define preempt_disable_notrace() do { } while (0)
-#define preempt_enable_no_resched_notrace() do { } while (0)
-#define preempt_enable_notrace() 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 sched_preempt_enable_no_resched() barrier()
+#define preempt_enable_no_resched() barrier()
+#define preempt_enable() barrier()
+
+#define preempt_disable_notrace() barrier()
+#define preempt_enable_no_resched_notrace() barrier()
+#define preempt_enable_notrace() barrier()
#endif /* CONFIG_PREEMPT_COUNT */