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authorFrederic Weisbecker <fweisbec@gmail.com>2013-05-02 17:37:49 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2013-05-02 17:54:19 +0200
commitc032862fba51a3ca504752d3a25186b324c5ce83 (patch)
tree955dc2ba4ab3df76ecc2bb780ee84aca04967e8d /include/linux/preempt.h
parentfda76e074c7737fc57855dd17c762e50ed526052 (diff)
parent8700c95adb033843fc163d112b9d21d4fda78018 (diff)
Merge commit '8700c95adb03' into timers/nohz
The full dynticks tree needs the latest RCU and sched upstream updates in order to fix some dependencies. Merge a common upstream merge point that has these updates. Conflicts: include/linux/perf_event.h kernel/rcutree.h kernel/rcutree_plugin.h Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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 5a710b9c578e..87a03c746f17 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 */