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-rw-r--r--include/linux/srcutiny.h47
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