1 files changed, 153 insertions, 0 deletions
diff --git a/kernel/rcu/rcu_segcblist.h b/kernel/rcu/rcu_segcblist.h
new file mode 100644
index 000000000..431cee212
--- /dev/null
+++ b/kernel/rcu/rcu_segcblist.h
@@ -0,0 +1,153 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * RCU segmented callback lists, internal-to-rcu header file
+ *
+ * Copyright IBM Corporation, 2017
+ *
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
+ */
+
+#include <linux/rcu_segcblist.h>
+
+/* Return number of callbacks in the specified callback list. */
+static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp)
+{
+	return READ_ONCE(rclp->len);
+}
+
+/* Return number of callbacks in segmented callback list by summing seglen. */
+long rcu_segcblist_n_segment_cbs(struct rcu_segcblist *rsclp);
+
+void rcu_cblist_init(struct rcu_cblist *rclp);
+void rcu_cblist_enqueue(struct rcu_cblist *rclp, struct rcu_head *rhp);
+void rcu_cblist_flush_enqueue(struct rcu_cblist *drclp,
+			      struct rcu_cblist *srclp,
+			      struct rcu_head *rhp);
+struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp);
+
+/*
+ * Is the specified rcu_segcblist structure empty?
+ *
+ * But careful!  The fact that the ->head field is NULL does not
+ * necessarily imply that there are no callbacks associated with
+ * this structure.  When callbacks are being invoked, they are
+ * removed as a group.  If callback invocation must be preempted,
+ * the remaining callbacks will be added back to the list.  Either
+ * way, the counts are updated later.
+ *
+ * So it is often the case that rcu_segcblist_n_cbs() should be used
+ * instead.
+ */
+static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp)
+{
+	return !READ_ONCE(rsclp->head);
+}
+
+/* Return number of callbacks in segmented callback list. */
+static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
+{
+#ifdef CONFIG_RCU_NOCB_CPU
+	return atomic_long_read(&rsclp->len);
+#else
+	return READ_ONCE(rsclp->len);
+#endif
+}
+
+static inline void rcu_segcblist_set_flags(struct rcu_segcblist *rsclp,
+					   int flags)
+{
+	WRITE_ONCE(rsclp->flags, rsclp->flags | flags);
+}
+
+static inline void rcu_segcblist_clear_flags(struct rcu_segcblist *rsclp,
+					     int flags)
+{
+	WRITE_ONCE(rsclp->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 rcu_segcblist_test_flags(rsclp, SEGCBLIST_ENABLED);
+}
+
+/*
+ * Is the specified rcu_segcblist NOCB offloaded (or in the middle of the
+ * [de]offloading process)?
+ */
+static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
+{
+	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
+	    rcu_segcblist_test_flags(rsclp, SEGCBLIST_LOCKING))
+		return true;
+
+	return false;
+}
+
+static inline bool rcu_segcblist_completely_offloaded(struct rcu_segcblist *rsclp)
+{
+	if (IS_ENABLED(CONFIG_RCU_NOCB_CPU) &&
+	    !rcu_segcblist_test_flags(rsclp, SEGCBLIST_RCU_CORE))
+		return true;
+
+	return false;
+}
+
+/*
+ * Are all segments following the specified segment of the specified
+ * rcu_segcblist structure empty of callbacks?  (The specified
+ * segment might well contain callbacks.)
+ */
+static inline bool rcu_segcblist_restempty(struct rcu_segcblist *rsclp, int seg)
+{
+	return !READ_ONCE(*READ_ONCE(rsclp->tails[seg]));
+}
+
+/*
+ * Is the specified segment of the specified rcu_segcblist structure
+ * empty of callbacks?
+ */
+static inline bool rcu_segcblist_segempty(struct rcu_segcblist *rsclp, int seg)
+{
+	if (seg == RCU_DONE_TAIL)
+		return &rsclp->head == rsclp->tails[RCU_DONE_TAIL];
+	return rsclp->tails[seg - 1] == rsclp->tails[seg];
+}
+
+void rcu_segcblist_inc_len(struct rcu_segcblist *rsclp);
+void rcu_segcblist_add_len(struct rcu_segcblist *rsclp, long v);
+void rcu_segcblist_init(struct rcu_segcblist *rsclp);
+void rcu_segcblist_disable(struct rcu_segcblist *rsclp);
+void rcu_segcblist_offload(struct rcu_segcblist *rsclp, bool offload);
+bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp);
+bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp);
+struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp);
+struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp);
+bool rcu_segcblist_nextgp(struct rcu_segcblist *rsclp, unsigned long *lp);
+void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
+			   struct rcu_head *rhp);
+bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
+			   struct rcu_head *rhp);
+void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp,
+				    struct rcu_cblist *rclp);
+void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp,
+				    struct rcu_cblist *rclp);
+void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp,
+				struct rcu_cblist *rclp);
+void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp,
+				   struct rcu_cblist *rclp);
+void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp,
+				   struct rcu_cblist *rclp);
+void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq);
+bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq);
+void rcu_segcblist_merge(struct rcu_segcblist *dst_rsclp,
+			 struct rcu_segcblist *src_rsclp);