rcu/nocb: Turn enabled/offload states into a common flag

This commit gathers the rcu_segcblist ->enabled and ->offloaded property
field into a single ->flags bitmask to avoid further proliferation of
individual u8 fields in the structure.  This change prepares for the
state formerly known as ->offloaded state to be modified at runtime.

Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Neeraj Upadhyay <neeraju@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Inspired-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 21 insertions, 2 deletions

diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h
index 18e101de8747..ff372db09f8b 100644
--- a/kernel/rcu/rcu_segcblist.h
+++ b/kernel/rcu/rcu_segcblist.h
@@ -53,19 +53,38 @@ static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
 #endif
 }
 
+static inline void rcu_segcblist_set_flags(struct rcu_segcblist *rsclp,
+					   int flags)
+{
+	rsclp->flags |= flags;
+}
+
+static inline void rcu_segcblist_clear_flags(struct rcu_segcblist *rsclp,
+					     int flags)
+{
+	rsclp->flags &= ~flags;
+}
+
+static inline bool rcu_segcblist_test_flags(struct rcu_segcblist *rsclp,
+					    int flags)
+{
+	return READ_ONCE(rsclp->flags) & flags;
+}
+
 /*
  * Is the specified rcu_segcblist enabled, for example, not corresponding
  * to an offline CPU?
  */
 static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
 {
-	return rsclp->enabled;
+	return rcu_segcblist_test_flags(rsclp, SEGCBLIST_ENABLED);
 }
 
 /* Is the specified rcu_segcblist offloaded?  */
 static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
 {
-	return IS_ENABLED(CONFIG_RCU_NOCB_CPU) && rsclp->offloaded;
+	return IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
+		rcu_segcblist_test_flags(rsclp, SEGCBLIST_OFFLOADED);
 }
 
 /*