kconfig: resync list.h

Update the existing macros and inline functions based on
include/linux/list.h.

The variable name '_new' can be reverted to 'new' because this header
is no longer included from the C++ file, scripts/kconfig/qconf.cc.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/kconfig/list.h

@@ -2,71 +2,56 @@
 #ifndef LIST_H
 #define LIST_H
 
-#include "list_types.h"
+#include <stddef.h>
 
-/*
- * Copied from include/linux/...
- */
+#include "list_types.h"
 
-#undef offsetof
-#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
+/* Are two types/vars the same type (ignoring qualifiers)? */
+#define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
 
 /**
  * container_of - cast a member of a structure out to the containing structure
- * @ptr:        the pointer to the member.
- * @type:       the type of the container struct this is embedded in.
- * @member:     the name of the member within the struct.
+ * @ptr:	the pointer to the member.
+ * @type:	the type of the container struct this is embedded in.
+ * @member:	the name of the member within the struct.
  *
  */
-#define container_of(ptr, type, member) ({                      \
-	const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
-	(type *)( (char *)__mptr - offsetof(type,member) );})
-
-#define LIST_HEAD_INIT(name) { &(name), &(name) }
+#define container_of(ptr, type, member) ({				\
+	void *__mptr = (void *)(ptr);					\
+	_Static_assert(__same_type(*(ptr), ((type *)0)->member) ||	\
+		      __same_type(*(ptr), void),			\
+		      "pointer type mismatch in container_of()");	\
+	((type *)(__mptr - offsetof(type, member))); })
 
-#define LIST_HEAD(name) \
-	struct list_head name = LIST_HEAD_INIT(name)
+#define LIST_POISON1  ((void *) 0x100)
+#define LIST_POISON2  ((void *) 0x122)
 
-/**
- * list_entry - get the struct for this entry
- * @ptr:	the &struct list_head pointer.
- * @type:	the type of the struct this is embedded in.
- * @member:	the name of the list_head within the struct.
+/*
+ * Circular doubly linked list implementation.
+ *
+ * Some of the internal functions ("__xxx") are useful when
+ * manipulating whole lists rather than single entries, as
+ * sometimes we already know the next/prev entries and we can
+ * generate better code by using them directly rather than
+ * using the generic single-entry routines.
  */
-#define list_entry(ptr, type, member) \
-	container_of(ptr, type, member)
 
-/**
- * list_for_each_entry	-	iterate over list of given type
- * @pos:	the type * to use as a loop cursor.
- * @head:	the head for your list.
- * @member:	the name of the list_head within the struct.
- */
-#define list_for_each_entry(pos, head, member)				\
-	for (pos = list_entry((head)->next, typeof(*pos), member);	\
-	     &pos->member != (head); 	\
-	     pos = list_entry(pos->member.next, typeof(*pos), member))
+#define LIST_HEAD_INIT(name) { &(name), &(name) }
 
-/**
- * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
- * @pos:	the type * to use as a loop cursor.
- * @n:		another type * to use as temporary storage
- * @head:	the head for your list.
- * @member:	the name of the list_head within the struct.
- */
-#define list_for_each_entry_safe(pos, n, head, member)			\
-	for (pos = list_entry((head)->next, typeof(*pos), member),	\
-		n = list_entry(pos->member.next, typeof(*pos), member);	\
-	     &pos->member != (head);					\
-	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
+#define LIST_HEAD(name) \
+	struct list_head name = LIST_HEAD_INIT(name)
 
 /**
- * list_empty - tests whether a list is empty
- * @head: the list to test.
+ * INIT_LIST_HEAD - Initialize a list_head structure
+ * @list: list_head structure to be initialized.
+ *
+ * Initializes the list_head to point to itself.  If it is a list header,
+ * the result is an empty list.
  */
-static inline int list_empty(const struct list_head *head)
+static inline void INIT_LIST_HEAD(struct list_head *list)
 {
-	return head->next == head;
+	list->next = list;
+	list->prev = list;
 }
 
 /*
@@ -75,14 +60,14 @@ static inline int list_empty(const struct list_head *head)
  * This is only for internal list manipulation where we know
  * the prev/next entries already!
  */
-static inline void __list_add(struct list_head *_new,
+static inline void __list_add(struct list_head *new,
 			      struct list_head *prev,
 			      struct list_head *next)
 {
-	next->prev = _new;
-	_new->next = next;
-	_new->prev = prev;
-	prev->next = _new;
+	next->prev = new;
+	new->next = next;
+	new->prev = prev;
+	prev->next = new;
 }
 
 /**
@@ -93,9 +78,9 @@ static inline void __list_add(struct list_head *_new,
  * Insert a new entry before the specified head.
  * This is useful for implementing queues.
  */
-static inline void list_add_tail(struct list_head *_new, struct list_head *head)
+static inline void list_add_tail(struct list_head *new, struct list_head *head)
 {
-	__list_add(_new, head->prev, head);
+	__list_add(new, head->prev, head);
 }
 
 /*
@@ -111,8 +96,11 @@ static inline void __list_del(struct list_head *prev, struct list_head *next)
 	prev->next = next;
 }
 
-#define LIST_POISON1  ((void *) 0x00100100)
-#define LIST_POISON2  ((void *) 0x00200200)
+static inline void __list_del_entry(struct list_head *entry)
+{
+	__list_del(entry->prev, entry->next);
+}
+
 /**
  * list_del - deletes entry from list.
  * @entry: the element to delete from the list.
@@ -121,8 +109,79 @@ static inline void __list_del(struct list_head *prev, struct list_head *next)
  */
 static inline void list_del(struct list_head *entry)
 {
-	__list_del(entry->prev, entry->next);
-	entry->next = (struct list_head*)LIST_POISON1;
-	entry->prev = (struct list_head*)LIST_POISON2;
+	__list_del_entry(entry);
+	entry->next = LIST_POISON1;
+	entry->prev = LIST_POISON2;
+}
+
+/**
+ * list_empty - tests whether a list is empty
+ * @head: the list to test.
+ */
+static inline int list_empty(const struct list_head *head)
+{
+	return head->next == head;
 }
-#endif
+
+/**
+ * list_entry - get the struct for this entry
+ * @ptr:	the &struct list_head pointer.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_entry(ptr, type, member) \
+	container_of(ptr, type, member)
+
+/**
+ * list_first_entry - get the first element from a list
+ * @ptr:	the list head to take the element from.
+ * @type:	the type of the struct this is embedded in.
+ * @member:	the name of the list_head within the struct.
+ *
+ * Note, that list is expected to be not empty.
+ */
+#define list_first_entry(ptr, type, member) \
+	list_entry((ptr)->next, type, member)
+
+/**
+ * list_next_entry - get the next element in list
+ * @pos:	the type * to cursor
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_next_entry(pos, member) \
+	list_entry((pos)->member.next, typeof(*(pos)), member)
+
+/**
+ * list_entry_is_head - test if the entry points to the head of the list
+ * @pos:	the type * to cursor
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_entry_is_head(pos, head, member)				\
+	(&pos->member == (head))
+
+/**
+ * list_for_each_entry - iterate over list of given type
+ * @pos:	the type * to use as a loop cursor.
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_for_each_entry(pos, head, member)				\
+	for (pos = list_first_entry(head, typeof(*pos), member);	\
+	     !list_entry_is_head(pos, head, member);			\
+	     pos = list_next_entry(pos, member))
+
+/**
+ * list_for_each_entry_safe - iterate over list of given type. Safe against removal of list entry
+ * @pos:	the type * to use as a loop cursor.
+ * @n:		another type * to use as temporary storage
+ * @head:	the head for your list.
+ * @member:	the name of the list_head within the struct.
+ */
+#define list_for_each_entry_safe(pos, n, head, member)			\
+	for (pos = list_first_entry(head, typeof(*pos), member),	\
+		n = list_next_entry(pos, member);			\
+	     !list_entry_is_head(pos, head, member);			\
+	     pos = n, n = list_next_entry(n, member))
+
+#endif /* LIST_H */