sync to Linus v4.13-rc2 for subsystem developers to work against

1 files changed, 22 insertions, 25 deletions

diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h
index 42311ee0334f..cfbfc540cafc 100644
--- a/include/linux/srcutiny.h
+++ b/include/linux/srcutiny.h
@@ -27,15 +27,14 @@
 #include <linux/swait.h>
 
 struct srcu_struct {
-	int srcu_lock_nesting[2];	/* srcu_read_lock() nesting depth. */
+	short srcu_lock_nesting[2];	/* srcu_read_lock() nesting depth. */
+	short srcu_idx;			/* Current reader array element. */
+	u8 srcu_gp_running;		/* GP workqueue running? */
+	u8 srcu_gp_waiting;		/* GP waiting for readers? */
 	struct swait_queue_head srcu_wq;
 					/* Last srcu_read_unlock() wakes GP. */
-	unsigned long srcu_gp_seq;	/* GP seq # for callback tagging. */
-	struct rcu_segcblist srcu_cblist;
-					/* Pending SRCU callbacks. */
-	int srcu_idx;			/* Current reader array element. */
-	bool srcu_gp_running;		/* GP workqueue running? */
-	bool srcu_gp_waiting;		/* GP waiting for readers? */
+	struct rcu_head *srcu_cb_head;	/* Pending callbacks: Head. */
+	struct rcu_head **srcu_cb_tail;	/* Pending callbacks: Tail. */
 	struct work_struct srcu_work;	/* For driving grace periods. */
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lockdep_map dep_map;
@@ -47,7 +46,7 @@ void srcu_drive_gp(struct work_struct *wp);
 #define __SRCU_STRUCT_INIT(name)					\
 {									\
 	.srcu_wq = __SWAIT_QUEUE_HEAD_INITIALIZER(name.srcu_wq),	\
-	.srcu_cblist = RCU_SEGCBLIST_INITIALIZER(name.srcu_cblist),	\
+	.srcu_cb_tail = &name.srcu_cb_head,				\
 	.srcu_work = __WORK_INITIALIZER(name.srcu_work, srcu_drive_gp),	\
 	__SRCU_DEP_MAP_INIT(name)					\
 }
@@ -63,31 +62,29 @@ void srcu_drive_gp(struct work_struct *wp);
 
 void synchronize_srcu(struct srcu_struct *sp);
 
-static inline void synchronize_srcu_expedited(struct srcu_struct *sp)
+/*
+ * Counts the new reader in the appropriate per-CPU element of the
+ * srcu_struct.  Can be invoked from irq/bh handlers, but the matching
+ * __srcu_read_unlock() must be in the same handler instance.  Returns an
+ * index that must be passed to the matching srcu_read_unlock().
+ */
+static inline int __srcu_read_lock(struct srcu_struct *sp)
 {
-	synchronize_srcu(sp);
-}
+	int idx;
 
-static inline void srcu_barrier(struct srcu_struct *sp)
-{
-	synchronize_srcu(sp);
+	idx = READ_ONCE(sp->srcu_idx);
+	WRITE_ONCE(sp->srcu_lock_nesting[idx], sp->srcu_lock_nesting[idx] + 1);
+	return idx;
 }
 
-static inline unsigned long srcu_batches_completed(struct srcu_struct *sp)
+static inline void synchronize_srcu_expedited(struct srcu_struct *sp)
 {
-	return 0;
+	synchronize_srcu(sp);
 }
 
-static inline void srcutorture_get_gp_data(enum rcutorture_type test_type,
-					   struct srcu_struct *sp, int *flags,
-					   unsigned long *gpnum,
-					   unsigned long *completed)
+static inline void srcu_barrier(struct srcu_struct *sp)
 {
-	if (test_type != SRCU_FLAVOR)
-		return;
-	*flags = 0;
-	*completed = sp->srcu_gp_seq;
-	*gpnum = *completed;
+	synchronize_srcu(sp);
 }
 
 #endif