[tip: perf/kprobes] llist: Add nonatomic __llist_add() and __llist_dell_all()

["tip-bot2 for Peter Zijlstra" <tip-bot2@xxxxxxxxxxxxx>]

The following commit has been merged into the perf/kprobes branch of tip:

Commit-ID:     476c5818c37a7828d558f34ae01f0c32f8bfadde
Gitweb:        https://git.kernel.org/tip/476c5818c37a7828d558f34ae01f0c32f8bfadde
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Sat, 29 Aug 2020 22:03:13 +09:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Mon, 12 Oct 2020 18:27:27 +02:00

llist: Add nonatomic __llist_add() and __llist_dell_all()

We'll use these in the new, lockless kretprobes code.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/159870619318.1229682.13027387548510028721.stgit@devnote2
---
 drivers/gpu/drm/i915/i915_request.c |  6 ------
 include/linux/llist.h               | 23 +++++++++++++++++++++++
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 0b2fe55..0e851b9 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -357,12 +357,6 @@ void i915_request_retire_upto(struct i915_request *rq)
 	} while (i915_request_retire(tmp) && tmp != rq);
 }
 
-static void __llist_add(struct llist_node *node, struct llist_head *head)
-{
-	node->next = head->first;
-	head->first = node;
-}
-
 static struct i915_request * const *
 __engine_active(struct intel_engine_cs *engine)
 {
diff --git a/include/linux/llist.h b/include/linux/llist.h
index 2e9c721..24f207b 100644
--- a/include/linux/llist.h
+++ b/include/linux/llist.h
@@ -197,6 +197,16 @@ static inline struct llist_node *llist_next(struct llist_node *node)
 extern bool llist_add_batch(struct llist_node *new_first,
 			    struct llist_node *new_last,
 			    struct llist_head *head);
+
+static inline bool __llist_add_batch(struct llist_node *new_first,
+				     struct llist_node *new_last,
+				     struct llist_head *head)
+{
+	new_last->next = head->first;
+	head->first = new_first;
+	return new_last->next == NULL;
+}
+
 /**
  * llist_add - add a new entry
  * @new:	new entry to be added
@@ -209,6 +219,11 @@ static inline bool llist_add(struct llist_node *new, struct llist_head *head)
 	return llist_add_batch(new, new, head);
 }
 
+static inline bool __llist_add(struct llist_node *new, struct llist_head *head)
+{
+	return __llist_add_batch(new, new, head);
+}
+
 /**
  * llist_del_all - delete all entries from lock-less list
  * @head:	the head of lock-less list to delete all entries
@@ -222,6 +237,14 @@ static inline struct llist_node *llist_del_all(struct llist_head *head)
 	return xchg(&head->first, NULL);
 }
 
+static inline struct llist_node *__llist_del_all(struct llist_head *head)
+{
+	struct llist_node *first = head->first;
+
+	head->first = NULL;
+	return first;
+}
+
 extern struct llist_node *llist_del_first(struct llist_head *head);
 
 struct llist_node *llist_reverse_order(struct llist_node *head);