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authorThomas Gleixner <tglx@linutronix.de>2013-04-24 20:33:46 +0200
committerThomas Gleixner <tglx@linutronix.de>2013-04-24 20:33:54 +0200
commit6402c7dc2a19c19bd8cdc7d80878b850da418942 (patch)
treecda2ea2df40442e2aa016119f3548cc504127ea8 /include/linux/preempt.h
parent77c675ba18836802f6b73d2d773481d06ebc0f04 (diff)
parent60d509fa6a9c4653a86ad830e4c4b30360b23f0e (diff)
Merge branch 'linus' into timers/core
Reason: Get upstream fixes before adding conflicting code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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 */