[PATCH tip/core/rcu 15/19] rcu: Remove RCU_STATE_INITIALIZER()

From: Paul E. McKenney
Date: Wed Aug 29 2018 - 18:22:46 EST


Now that a given build of the Linux kernel has only one set of rcu_state,
rcu_node, and rcu_data structures, there is no point in creating a macro
to declare and compile-time initialize them. This commit therefore
just does normal declaration and compile-time initialization of these
structures. While in the area, this commit also removes #ifndefs of
the no-longer-ever-defined preprocessor macro RCU_TREE_NONCORE.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcu/tree.c | 54 ++++++++++++-----------------------------------
kernel/rcu/tree.h | 29 +++++++++++++++++++------
2 files changed, 37 insertions(+), 46 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index a8965a7caf25..1868df8089ba 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -72,46 +72,20 @@

/* Data structures. */

-/*
- * In order to export the rcu_state name to the tracing tools, it
- * needs to be added in the __tracepoint_string section.
- * This requires defining a separate variable tp_<sname>_varname
- * that points to the string being used, and this will allow
- * the tracing userspace tools to be able to decipher the string
- * address to the matching string.
- */
-#ifdef CONFIG_TRACING
-# define DEFINE_RCU_TPS(sname) \
-static char sname##_varname[] = #sname; \
-static const char *tp_##sname##_varname __used __tracepoint_string = sname##_varname;
-# define RCU_STATE_NAME(sname) sname##_varname
-#else
-# define DEFINE_RCU_TPS(sname)
-# define RCU_STATE_NAME(sname) __stringify(sname)
-#endif
-
-#define RCU_STATE_INITIALIZER(sname, sabbr, cr) \
-DEFINE_RCU_TPS(sname) \
-static DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, rcu_data); \
-struct rcu_state rcu_state = { \
- .level = { &rcu_state.node[0] }, \
- .rda = &rcu_data, \
- .call = cr, \
- .gp_state = RCU_GP_IDLE, \
- .gp_seq = (0UL - 300UL) << RCU_SEQ_CTR_SHIFT, \
- .barrier_mutex = __MUTEX_INITIALIZER(rcu_state.barrier_mutex), \
- .name = RCU_STATE_NAME(sname), \
- .abbr = sabbr, \
- .exp_mutex = __MUTEX_INITIALIZER(rcu_state.exp_mutex), \
- .exp_wake_mutex = __MUTEX_INITIALIZER(rcu_state.exp_wake_mutex), \
- .ofl_lock = __SPIN_LOCK_UNLOCKED(rcu_state.ofl_lock), \
-}
-
-#ifdef CONFIG_PREEMPT_RCU
-RCU_STATE_INITIALIZER(rcu_preempt, 'p', call_rcu);
-#else
-RCU_STATE_INITIALIZER(rcu_sched, 's', call_rcu);
-#endif
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, rcu_data);
+struct rcu_state rcu_state = {
+ .level = { &rcu_state.node[0] },
+ .rda = &rcu_data,
+ .call = call_rcu,
+ .gp_state = RCU_GP_IDLE,
+ .gp_seq = (0UL - 300UL) << RCU_SEQ_CTR_SHIFT,
+ .barrier_mutex = __MUTEX_INITIALIZER(rcu_state.barrier_mutex),
+ .name = RCU_NAME,
+ .abbr = RCU_ABBR,
+ .exp_mutex = __MUTEX_INITIALIZER(rcu_state.exp_mutex),
+ .exp_wake_mutex = __MUTEX_INITIALIZER(rcu_state.exp_wake_mutex),
+ .ofl_lock = __SPIN_LOCK_UNLOCKED(rcu_state.ofl_lock),
+};

static struct rcu_state *const rcu_state_p = &rcu_state;
static struct rcu_data __percpu *const rcu_data_p = &rcu_data;
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 38658ca87dcb..3f36562d3118 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -386,7 +386,6 @@ struct rcu_state {
#define RCU_GP_CLEANUP 7 /* Grace-period cleanup started. */
#define RCU_GP_CLEANED 8 /* Grace-period cleanup complete. */

-#ifndef RCU_TREE_NONCORE
static const char * const gp_state_names[] = {
"RCU_GP_IDLE",
"RCU_GP_WAIT_GPS",
@@ -398,7 +397,29 @@ static const char * const gp_state_names[] = {
"RCU_GP_CLEANUP",
"RCU_GP_CLEANED",
};
-#endif /* #ifndef RCU_TREE_NONCORE */
+
+/*
+ * In order to export the rcu_state name to the tracing tools, it
+ * needs to be added in the __tracepoint_string section.
+ * This requires defining a separate variable tp_<sname>_varname
+ * that points to the string being used, and this will allow
+ * the tracing userspace tools to be able to decipher the string
+ * address to the matching string.
+ */
+#ifdef CONFIG_PREEMPT_RCU
+#define RCU_ABBR 'p'
+#define RCU_NAME_RAW "rcu_preempt"
+#else /* #ifdef CONFIG_PREEMPT_RCU */
+#define RCU_ABBR 's'
+#define RCU_NAME_RAW "rcu_sched"
+#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+#ifndef CONFIG_TRACING
+#define RCU_NAME RCU_NAME_RAW
+#else /* #ifdef CONFIG_TRACING */
+static char rcu_name[] = RCU_NAME_RAW;
+static const char *tp_rcu_varname __used __tracepoint_string = rcu_name;
+#define RCU_NAME rcu_name
+#endif /* #else #ifdef CONFIG_TRACING */

extern struct list_head rcu_struct_flavors;

@@ -426,8 +447,6 @@ DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
DECLARE_PER_CPU(char, rcu_cpu_has_work);
#endif /* #ifdef CONFIG_RCU_BOOST */

-#ifndef RCU_TREE_NONCORE
-
/* Forward declarations for rcutree_plugin.h */
static void rcu_bootup_announce(void);
static void rcu_qs(void);
@@ -495,5 +514,3 @@ void srcu_offline_cpu(unsigned int cpu);
void srcu_online_cpu(unsigned int cpu) { }
void srcu_offline_cpu(unsigned int cpu) { }
#endif /* #else #ifdef CONFIG_SRCU */
-
-#endif /* #ifndef RCU_TREE_NONCORE */
--
2.17.1