Change the old hlist_bl_first_rcu to hlist_bl_first_rcu_dereference
to indicate that it is a RCU dereference.
Add hlist_bl_next_rcu and hlist_bl_first_rcu to use RCU pointers
and use them to fix sparse warnings.
Add hlist_bl_for_each_entry_continue_rcu.
Signed-off-by: Julian Anastasov <ja@xxxxxx>
---
include/linux/rculist_bl.h | 49 +++++++++++++++++++++++++++++++-------
1 file changed, 40 insertions(+), 9 deletions(-)
diff --git a/include/linux/rculist_bl.h b/include/linux/rculist_bl.h
index 0b952d06eb0b..36363b876e53 100644
--- a/include/linux/rculist_bl.h
+++ b/include/linux/rculist_bl.h
@@ -8,21 +8,31 @@
#include <linux/list_bl.h>
#include <linux/rcupdate.h>
+/* return the first ptr or next element in an RCU protected list */
+#define hlist_bl_first_rcu(head) \
+ (*((struct hlist_bl_node __rcu **)(&(head)->first)))
+#define hlist_bl_next_rcu(node) \
+ (*((struct hlist_bl_node __rcu **)(&(node)->next)))
+
static inline void hlist_bl_set_first_rcu(struct hlist_bl_head *h,
struct hlist_bl_node *n)
{
LIST_BL_BUG_ON((unsigned long)n & LIST_BL_LOCKMASK);
LIST_BL_BUG_ON(((unsigned long)h->first & LIST_BL_LOCKMASK) !=
LIST_BL_LOCKMASK);
- rcu_assign_pointer(h->first,
+ rcu_assign_pointer(hlist_bl_first_rcu(h),
(struct hlist_bl_node *)((unsigned long)n | LIST_BL_LOCKMASK));
}
-static inline struct hlist_bl_node *hlist_bl_first_rcu(struct hlist_bl_head *h)
-{
- return (struct hlist_bl_node *)
- ((unsigned long)rcu_dereference_check(h->first, hlist_bl_is_locked(h)) & ~LIST_BL_LOCKMASK);
-}
+#define hlist_bl_first_rcu_dereference(head) \
+({ \
+ struct hlist_bl_head *__head = (head); \
+ \
+ (struct hlist_bl_node *) \
+ ((unsigned long)rcu_dereference_check(hlist_bl_first_rcu(__head), \
+ hlist_bl_is_locked(__head)) & \
+ ~LIST_BL_LOCKMASK); \
+})
/**
* hlist_bl_del_rcu - deletes entry from hash list without re-initialization
@@ -73,7 +83,7 @@ static inline void hlist_bl_add_head_rcu(struct hlist_bl_node *n,
{
struct hlist_bl_node *first;
- /* don't need hlist_bl_first_rcu because we're under lock */
+ /* don't need hlist_bl_first_rcu* because we're under lock */
first = hlist_bl_first(h);
n->next = first;
@@ -93,9 +103,30 @@ static inline void hlist_bl_add_head_rcu(struct hlist_bl_node *n,
*
*/
#define hlist_bl_for_each_entry_rcu(tpos, pos, head, member) \
- for (pos = hlist_bl_first_rcu(head); \
+ for (pos = hlist_bl_first_rcu_dereference(head); \
pos && \
({ tpos = hlist_bl_entry(pos, typeof(*tpos), member); 1; }); \
- pos = rcu_dereference_raw(pos->next))
+ pos = rcu_dereference_raw(hlist_bl_next_rcu(pos)))
+
+/**
+ * hlist_bl_for_each_entry_continue_rcu - continue iteration over list of given
+ * type
+ * @tpos: the type * to use as a loop cursor.
+ * @pos: the &struct hlist_bl_node to use as a loop cursor.
+ * @member: the name of the hlist_bl_node within the struct.
+ *
+ * Continue to iterate over list of given type, continuing after
+ * the current position which must have been in the list when the RCU read
+ * lock was taken.
+ * This would typically require either that you obtained the node from a
+ * previous walk of the list in the same RCU read-side critical section, or
+ * that you held some sort of non-RCU reference (such as a reference count)
+ * to keep the node alive *and* in the list.
+ */
+#define hlist_bl_for_each_entry_continue_rcu(tpos, pos, member) \
+ for (pos = rcu_dereference_raw(hlist_bl_next_rcu(&(tpos)->member)); \
+ pos && \
+ ({ tpos = hlist_bl_entry(pos, typeof(*tpos), member); 1; }); \
+ pos = rcu_dereference_raw(hlist_bl_next_rcu(pos)))
#endif
--
2.43.0
