rcu: Make rcu_sleep_check() also check rcu_lock_map

Although it is OK to be preempted in an RCU read-side critical section
for TREE_PREEMPT_RCU, it is definitely not OK to be preempted, block,
or might_sleep() within an RCU read-side critical section for TREE_RCU.
Unfortunately, rcu_might_sleep() currently only checks for RCU-bh and
RCU-sched read-side critical sections.  This commit therefore makes
rcu_might_sleep() check for RCU read-side critical sections, but only
in TREE_RCU builds.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

include/linux/rcupdate.h

@@ -381,8 +381,22 @@ extern int rcu_my_thread_group_empty(void);
 		}							\
 	} while (0)
 
+#if defined(CONFIG_PROVE_RCU) && !defined(CONFIG_PREEMPT_RCU)
+static inline void rcu_preempt_sleep_check(void)
+{
+	rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
+			   "Illegal context switch in RCU read-side "
+			   "critical section");
+}
+#else /* #ifdef CONFIG_PROVE_RCU */
+static inline void rcu_preempt_sleep_check(void)
+{
+}
+#endif /* #else #ifdef CONFIG_PROVE_RCU */
+
 #define rcu_sleep_check()						\
 	do {								\
+		rcu_preempt_sleep_check();				\
 		rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map),	\
 				   "Illegal context switch in RCU-bh"	\
 				   " read-side critical section");	\