Hi Jason,
Today's linux-next merge of the kgdb tree got a conflict in
include/linux/rcupdate.h between commits
551d55a944b143ef26fbd482d1c463199d6f65cf ("tree/tiny rcu: Add debug RCU
head objects") and f5155b33277c9678041a27869165619bb34f722f ("rcu: add an
rcu_dereference_index_check()") from Linus' tree and commit
9e213357d0aeaeb81e213cfd3b9415db5fccc1b5 ("rcu,debug_core: allow the
kernel debugger to reset the rcu stall timer") from the kgdb tree.
Just overlapping additions. I fixed it up (see below) and can carry the
fix for a while.
--
Cheers,
Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
diff --cc include/linux/rcupdate.h
index 9fbc54a,585efef..0000000
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@@ -529,74 -517,12 +529,82 @@@ extern void call_rcu(struct rcu_head *h
extern void call_rcu_bh(struct rcu_head *head,
void (*func)(struct rcu_head *head));
+/*
+ * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally
+ * by call_rcu() and rcu callback execution, and are therefore not part of the
+ * RCU API. Leaving in rcupdate.h because they are used by all RCU flavors.
+ */
+
+#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
+# define STATE_RCU_HEAD_READY 0
+# define STATE_RCU_HEAD_QUEUED 1
+
+extern struct debug_obj_descr rcuhead_debug_descr;
+
+static inline void debug_rcu_head_queue(struct rcu_head *head)
+{
+ debug_object_activate(head, &rcuhead_debug_descr);
+ debug_object_active_state(head, &rcuhead_debug_descr,
+ STATE_RCU_HEAD_READY,
+ STATE_RCU_HEAD_QUEUED);
+}
+
+static inline void debug_rcu_head_unqueue(struct rcu_head *head)
+{
+ debug_object_active_state(head, &rcuhead_debug_descr,
+ STATE_RCU_HEAD_QUEUED,
+ STATE_RCU_HEAD_READY);
+ debug_object_deactivate(head, &rcuhead_debug_descr);
+}
+#else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+static inline void debug_rcu_head_queue(struct rcu_head *head)
+{
+}
+
+static inline void debug_rcu_head_unqueue(struct rcu_head *head)
+{
+}
+#endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+
+#ifndef CONFIG_PROVE_RCU
+#define __do_rcu_dereference_check(c) do { } while (0)
+#endif /* #ifdef CONFIG_PROVE_RCU */
+
+#define __rcu_dereference_index_check(p, c) \
+ ({ \
+ typeof(p) _________p1 = ACCESS_ONCE(p); \
+ __do_rcu_dereference_check(c); \
+ smp_read_barrier_depends(); \
+ (_________p1); \
+ })
+
+/**
+ * rcu_dereference_index_check() - rcu_dereference for indices with debug checking
+ * @p: The pointer to read, prior to dereferencing
+ * @c: The conditions under which the dereference will take place
+ *
+ * Similar to rcu_dereference_check(), but omits the sparse checking.
+ * This allows rcu_dereference_index_check() to be used on integers,
+ * which can then be used as array indices. Attempting to use
+ * rcu_dereference_check() on an integer will give compiler warnings
+ * because the sparse address-space mechanism relies on dereferencing
+ * the RCU-protected pointer. Dereferencing integers is not something
+ * that even gcc will put up with.
+ *
+ * Note that this function does not implicitly check for RCU read-side
+ * critical sections. If this function gains lots of uses, it might
+ * make sense to provide versions for each flavor of RCU, but it does
+ * not make sense as of early 2010.
+ */
+#define rcu_dereference_index_check(p, c) \
+ __rcu_dereference_index_check((p), (c))
+
+ #ifdef CONFIG_RCU_CPU_STALL_DETECTOR
+ extern void rcu_cpu_stall_reset(void);
+ #else /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
+ static void rcu_cpu_stall_reset()
+ {
+ }
+ #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
+
#endif /* __LINUX_RCUPDATE_H */
--
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