Merge git://git.kernel.org/pub/scm/linux/kernel/git/lethal/fbdev-2.6

[pandora-kernel.git] / kernel / rcupdate.c

diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index f3240e9..7784bd2 100644 (file)
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -142,10 +142,17 @@ static int rcuhead_fixup_init(void *addr, enum debug_obj_state state)
                 * Ensure that queued callbacks are all executed.
                 * If we detect that we are nested in a RCU read-side critical
                 * section, we should simply fail, otherwise we would deadlock.
+                * In !PREEMPT configurations, there is no way to tell if we are
+                * in a RCU read-side critical section or not, so we never
+                * attempt any fixup and just print a warning.
                 */
+#ifndef CONFIG_PREEMPT
+               WARN_ON_ONCE(1);
+               return 0;
+#endif
                if (rcu_preempt_depth() != 0 || preempt_count() != 0 ||
                    irqs_disabled()) {
-                       WARN_ON(1);
+                       WARN_ON_ONCE(1);
                        return 0;
                }
                rcu_barrier();
@@ -184,10 +191,17 @@ static int rcuhead_fixup_activate(void *addr, enum debug_obj_state state)
                 * Ensure that queued callbacks are all executed.
                 * If we detect that we are nested in a RCU read-side critical
                 * section, we should simply fail, otherwise we would deadlock.
+                * In !PREEMPT configurations, there is no way to tell if we are
+                * in a RCU read-side critical section or not, so we never
+                * attempt any fixup and just print a warning.
                 */
+#ifndef CONFIG_PREEMPT
+               WARN_ON_ONCE(1);
+               return 0;
+#endif
                if (rcu_preempt_depth() != 0 || preempt_count() != 0 ||
                    irqs_disabled()) {
-                       WARN_ON(1);
+                       WARN_ON_ONCE(1);
                        return 0;
                }
                rcu_barrier();
@@ -214,15 +228,17 @@ static int rcuhead_fixup_free(void *addr, enum debug_obj_state state)
                 * Ensure that queued callbacks are all executed.
                 * If we detect that we are nested in a RCU read-side critical
                 * section, we should simply fail, otherwise we would deadlock.
-                * Note that the machinery to reliably determine whether
-                * or not we are in an RCU read-side critical section
-                * exists only in the preemptible RCU implementations
-                * (TINY_PREEMPT_RCU and TREE_PREEMPT_RCU), which is why
-                * DEBUG_OBJECTS_RCU_HEAD is disallowed if !PREEMPT.
+                * In !PREEMPT configurations, there is no way to tell if we are
+                * in a RCU read-side critical section or not, so we never
+                * attempt any fixup and just print a warning.
                 */
+#ifndef CONFIG_PREEMPT
+               WARN_ON_ONCE(1);
+               return 0;
+#endif
                if (rcu_preempt_depth() != 0 || preempt_count() != 0 ||
                    irqs_disabled()) {
-                       WARN_ON(1);
+                       WARN_ON_ONCE(1);
                        return 0;
                }
                rcu_barrier();