[PATCH 28/38] ubifs: add complete version of list.h
Dongsheng Yang
yangds.fnst at cn.fujitsu.com
Mon Dec 21 00:41:51 PST 2015
From: Richard Weinberger <richard at nod.at>
See http://lists.infradead.org/pipermail/linux-mtd/2015-October/062421.html
Signed-off-by: Richard Weinberger <richard at nod.at>
---
ubifs-utils/include/list.h | 305 +++++++++++++++++++++++++++++++--------------
1 file changed, 213 insertions(+), 92 deletions(-)
diff --git a/ubifs-utils/include/list.h b/ubifs-utils/include/list.h
index 0cffa33..080ea39 100644
--- a/ubifs-utils/include/list.h
+++ b/ubifs-utils/include/list.h
@@ -17,6 +17,10 @@
#ifndef _LINUX_LIST_H
#define _LINUX_LIST_H
+struct list_head {
+ struct list_head *next, *prev;
+};
+
#define LIST_POISON1 ((struct list_head *) 0x00100100)
#define LIST_POISON2 ((struct list_head *) 0x00200200)
@@ -30,10 +34,6 @@
* using the generic single-entry routines.
*/
-struct list_head {
- struct list_head *next, *prev;
-};
-
#define LIST_HEAD_INIT(name) { &(name), &(name) }
#define LIST_HEAD(name) \
@@ -52,17 +52,17 @@ static inline void INIT_LIST_HEAD(struct list_head *list)
* the prev/next entries already!
*/
#ifndef CONFIG_DEBUG_LIST
-static inline void __list_add(struct list_head *xnew,
+static inline void __list_add(struct list_head *new,
struct list_head *prev,
struct list_head *next)
{
- next->prev = xnew;
- xnew->next = next;
- xnew->prev = prev;
- prev->next = xnew;
+ next->prev = new;
+ new->next = next;
+ new->prev = prev;
+ prev->next = new;
}
#else
-extern void __list_add(struct list_head *xnew,
+extern void __list_add(struct list_head *new,
struct list_head *prev,
struct list_head *next);
#endif
@@ -75,14 +75,10 @@ extern void __list_add(struct list_head *xnew,
* Insert a new entry after the specified head.
* This is good for implementing stacks.
*/
-#ifndef CONFIG_DEBUG_LIST
-static inline void list_add(struct list_head *xnew, struct list_head *head)
+static inline void list_add(struct list_head *new, struct list_head *head)
{
- __list_add(xnew, head, head->next);
+ __list_add(new, head, head->next);
}
-#else
-extern void list_add(struct list_head *xnew, struct list_head *head);
-#endif
/**
@@ -93,9 +89,9 @@ extern void list_add(struct list_head *xnew, struct list_head *head);
* Insert a new entry before the specified head.
* This is useful for implementing queues.
*/
-static inline void list_add_tail(struct list_head *xnew, struct list_head *head)
+static inline void list_add_tail(struct list_head *new, struct list_head *head)
{
- __list_add(xnew, head->prev, head);
+ __list_add(new, head->prev, head);
}
/*
@@ -114,10 +110,15 @@ static inline void __list_del(struct list_head * prev, struct list_head * next)
/**
* list_del - deletes entry from list.
* @entry: the element to delete from the list.
- * Note: list_empty on entry does not return true after this, the entry is
+ * Note: list_empty() on entry does not return true after this, the entry is
* in an undefined state.
*/
#ifndef CONFIG_DEBUG_LIST
+static inline void __list_del_entry(struct list_head *entry)
+{
+ __list_del(entry->prev, entry->next);
+}
+
static inline void list_del(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
@@ -125,6 +126,7 @@ static inline void list_del(struct list_head *entry)
entry->prev = LIST_POISON2;
}
#else
+extern void __list_del_entry(struct list_head *entry);
extern void list_del(struct list_head *entry);
#endif
@@ -132,30 +134,32 @@ extern void list_del(struct list_head *entry);
* list_replace - replace old entry by new one
* @old : the element to be replaced
* @new : the new element to insert
- * Note: if 'old' was empty, it will be overwritten.
+ *
+ * If @old was empty, it will be overwritten.
*/
static inline void list_replace(struct list_head *old,
- struct list_head *xnew)
+ struct list_head *new)
{
- xnew->next = old->next;
- xnew->next->prev = xnew;
- xnew->prev = old->prev;
- xnew->prev->next = xnew;
+ new->next = old->next;
+ new->next->prev = new;
+ new->prev = old->prev;
+ new->prev->next = new;
}
static inline void list_replace_init(struct list_head *old,
- struct list_head *xnew)
+ struct list_head *new)
{
- list_replace(old, xnew);
+ list_replace(old, new);
INIT_LIST_HEAD(old);
}
+
/**
* list_del_init - deletes entry from list and reinitialize it.
* @entry: the element to delete from the list.
*/
static inline void list_del_init(struct list_head *entry)
{
- __list_del(entry->prev, entry->next);
+ __list_del_entry(entry);
INIT_LIST_HEAD(entry);
}
@@ -166,8 +170,8 @@ static inline void list_del_init(struct list_head *entry)
*/
static inline void list_move(struct list_head *list, struct list_head *head)
{
- __list_del(list->prev, list->next);
- list_add(list, head);
+ __list_del_entry(list);
+ list_add(list, head);
}
/**
@@ -178,8 +182,8 @@ static inline void list_move(struct list_head *list, struct list_head *head)
static inline void list_move_tail(struct list_head *list,
struct list_head *head)
{
- __list_del(list->prev, list->next);
- list_add_tail(list, head);
+ __list_del_entry(list);
+ list_add_tail(list, head);
}
/**
@@ -221,6 +225,69 @@ static inline int list_empty_careful(const struct list_head *head)
return (next == head) && (next == head->prev);
}
+/**
+ * list_rotate_left - rotate the list to the left
+ * @head: the head of the list
+ */
+static inline void list_rotate_left(struct list_head *head)
+{
+ struct list_head *first;
+
+ if (!list_empty(head)) {
+ first = head->next;
+ list_move_tail(first, head);
+ }
+}
+
+/**
+ * list_is_singular - tests whether a list has just one entry.
+ * @head: the list to test.
+ */
+static inline int list_is_singular(const struct list_head *head)
+{
+ return !list_empty(head) && (head->next == head->prev);
+}
+
+static inline void __list_cut_position(struct list_head *list,
+ struct list_head *head, struct list_head *entry)
+{
+ struct list_head *new_first = entry->next;
+ list->next = head->next;
+ list->next->prev = list;
+ list->prev = entry;
+ entry->next = list;
+ head->next = new_first;
+ new_first->prev = head;
+}
+
+/**
+ * list_cut_position - cut a list into two
+ * @list: a new list to add all removed entries
+ * @head: a list with entries
+ * @entry: an entry within head, could be the head itself
+ * and if so we won't cut the list
+ *
+ * This helper moves the initial part of @head, up to and
+ * including @entry, from @head to @list. You should
+ * pass on @entry an element you know is on @head. @list
+ * should be an empty list or a list you do not care about
+ * losing its data.
+ *
+ */
+static inline void list_cut_position(struct list_head *list,
+ struct list_head *head, struct list_head *entry)
+{
+ if (list_empty(head))
+ return;
+ if (list_is_singular(head) &&
+ (head->next != entry && head != entry))
+ return;
+ if (entry == head)
+ INIT_LIST_HEAD(list);
+ else
+ __list_cut_position(list, head, entry);
+}
+
static inline void __list_splice(const struct list_head *list,
struct list_head *prev,
struct list_head *next)
@@ -236,11 +303,12 @@ static inline void __list_splice(const struct list_head *list,
}
/**
- * list_splice - join two lists
+ * list_splice - join two lists, this is designed for stacks
* @list: the new list to add.
* @head: the place to add it in the first list.
*/
-static inline void list_splice(struct list_head *list, struct list_head *head)
+static inline void list_splice(const struct list_head *list,
+ struct list_head *head)
{
if (!list_empty(list))
__list_splice(list, head, head->next);
@@ -295,7 +363,7 @@ static inline void list_splice_tail_init(struct list_head *list,
* 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_struct within the struct.
+ * @member: the name of the list_head within the struct.
*/
#define list_entry(ptr, type, member) \
container_of(ptr, type, member)
@@ -304,7 +372,7 @@ static inline void list_splice_tail_init(struct list_head *list,
* 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_struct within the struct.
+ * @member: the name of the list_head within the struct.
*
* Note, that list is expected to be not empty.
*/
@@ -312,35 +380,49 @@ static inline void list_splice_tail_init(struct list_head *list,
list_entry((ptr)->next, type, member)
/**
- * list_next_entry - get the next element from a list
+ * list_last_entry - get the last element from a list
* @ptr: the list head to take the element from.
- * @member: the name of the list_struct within the struct.
+ * @type: the type of the struct this is embedded in.
+ * @member: the name of the list_head within the struct.
*
- * Note, that next is expected to be not null.
+ * Note, that list is expected to be not empty.
*/
-#define list_next_entry(ptr, member) \
- list_entry((ptr)->member.next, typeof(*ptr), member)
+#define list_last_entry(ptr, type, member) \
+ list_entry((ptr)->prev, type, member)
/**
- * list_for_each - iterate over a list
- * @pos: the &struct list_head to use as a loop cursor.
- * @head: the head for your list.
+ * list_first_entry_or_null - 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 if the list is empty, it returns NULL.
*/
-#define list_for_each(pos, head) \
- for (pos = (head)->next; pos != (head); \
- pos = pos->next)
+#define list_first_entry_or_null(ptr, type, member) \
+ (!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL)
+
+/**
+ * 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_for_each - iterate over a list
+ * list_prev_entry - get the prev element in list
+ * @pos: the type * to cursor
+ * @member: the name of the list_head within the struct.
+ */
+#define list_prev_entry(pos, member) \
+ list_entry((pos)->member.prev, typeof(*(pos)), member)
+
+/**
+ * list_for_each - iterate over a list
* @pos: the &struct list_head to use as a loop cursor.
* @head: the head for your list.
- *
- * This variant differs from list_for_each() in that it's the
- * simplest possible list iteration code, no prefetching is done.
- * Use this for code that knows the list to be very short (empty
- * or 1 entry) most of the time.
*/
-#define __list_for_each(pos, head) \
+#define list_for_each(pos, head) \
for (pos = (head)->next; pos != (head); pos = pos->next)
/**
@@ -349,8 +431,7 @@ static inline void list_splice_tail_init(struct list_head *list,
* @head: the head for your list.
*/
#define list_for_each_prev(pos, head) \
- for (pos = (head)->prev; pos != (head); \
- pos = pos->prev)
+ for (pos = (head)->prev; pos != (head); pos = pos->prev)
/**
* list_for_each_safe - iterate over a list safe against removal of list entry
@@ -363,34 +444,45 @@ static inline void list_splice_tail_init(struct list_head *list,
pos = n, n = pos->next)
/**
+ * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
+ * @pos: the &struct list_head to use as a loop cursor.
+ * @n: another &struct list_head to use as temporary storage
+ * @head: the head for your list.
+ */
+#define list_for_each_prev_safe(pos, n, head) \
+ for (pos = (head)->prev, n = pos->prev; \
+ pos != (head); \
+ pos = n, n = pos->prev)
+
+/**
* 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_struct within the struct.
+ * @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))
+ for (pos = list_first_entry(head, typeof(*pos), member); \
+ &pos->member != (head); \
+ pos = list_next_entry(pos, member))
/**
* list_for_each_entry_reverse - iterate backwards 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_struct within the struct.
+ * @member: the name of the list_head within the struct.
*/
#define list_for_each_entry_reverse(pos, head, member) \
- for (pos = list_entry((head)->prev, typeof(*pos), member); \
- &pos->member != (head); \
- pos = list_entry(pos->member.prev, typeof(*pos), member))
+ for (pos = list_last_entry(head, typeof(*pos), member); \
+ &pos->member != (head); \
+ pos = list_prev_entry(pos, member))
/**
- * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue
+ * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
* @pos: the type * to use as a start point
* @head: the head of the list
- * @member: the name of the list_struct within the struct.
+ * @member: the name of the list_head within the struct.
*
- * Prepares a pos entry for use as a start point in list_for_each_entry_continue.
+ * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
*/
#define list_prepare_entry(pos, head, member) \
((pos) ? : list_entry(head, typeof(*pos), member))
@@ -399,86 +491,115 @@ static inline void list_splice_tail_init(struct list_head *list,
* list_for_each_entry_continue - continue iteration 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_struct within the struct.
+ * @member: the name of the list_head within the struct.
*
* Continue to iterate over list of given type, continuing after
* the current position.
*/
#define list_for_each_entry_continue(pos, head, member) \
- for (pos = list_entry(pos->member.next, typeof(*pos), member); \
- &pos->member != (head); \
- pos = list_entry(pos->member.next, typeof(*pos), member))
+ for (pos = list_next_entry(pos, member); \
+ &pos->member != (head); \
+ pos = list_next_entry(pos, member))
+
+/**
+ * list_for_each_entry_continue_reverse - iterate backwards from the given point
+ * @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.
+ *
+ * Start to iterate over list of given type backwards, continuing after
+ * the current position.
+ */
+#define list_for_each_entry_continue_reverse(pos, head, member) \
+ for (pos = list_prev_entry(pos, member); \
+ &pos->member != (head); \
+ pos = list_prev_entry(pos, member))
/**
* list_for_each_entry_from - iterate over list of given type from the current point
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
- * @member: the name of the list_struct within the struct.
+ * @member: the name of the list_head within the struct.
*
* Iterate over list of given type, continuing from current position.
*/
#define list_for_each_entry_from(pos, head, member) \
- for (; &pos->member != (head); \
- pos = list_entry(pos->member.next, typeof(*pos), member))
+ for (; &pos->member != (head); \
+ 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_struct within the struct.
+ * @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); \
+ for (pos = list_first_entry(head, typeof(*pos), member), \
+ n = list_next_entry(pos, member); \
&pos->member != (head); \
- pos = n, n = list_entry(n->member.next, typeof(*n), member))
+ pos = n, n = list_next_entry(n, member))
/**
- * list_for_each_entry_safe_continue
+ * list_for_each_entry_safe_continue - continue list iteration safe against removal
* @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_struct within the struct.
+ * @member: the name of the list_head within the struct.
*
* Iterate over list of given type, continuing after current point,
* safe against removal of list entry.
*/
#define list_for_each_entry_safe_continue(pos, n, head, member) \
- for (pos = list_entry(pos->member.next, typeof(*pos), member), \
- n = list_entry(pos->member.next, typeof(*pos), member); \
+ for (pos = list_next_entry(pos, member), \
+ n = list_next_entry(pos, member); \
&pos->member != (head); \
- pos = n, n = list_entry(n->member.next, typeof(*n), member))
+ pos = n, n = list_next_entry(n, member))
/**
- * list_for_each_entry_safe_from
+ * list_for_each_entry_safe_from - iterate over list from current point safe against removal
* @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_struct within the struct.
+ * @member: the name of the list_head within the struct.
*
* Iterate over list of given type from current point, safe against
* removal of list entry.
*/
#define list_for_each_entry_safe_from(pos, n, head, member) \
- for (n = list_entry(pos->member.next, typeof(*pos), member); \
+ for (n = list_next_entry(pos, member); \
&pos->member != (head); \
- pos = n, n = list_entry(n->member.next, typeof(*n), member))
+ pos = n, n = list_next_entry(n, member))
/**
- * list_for_each_entry_safe_reverse
+ * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
* @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_struct within the struct.
+ * @member: the name of the list_head within the struct.
*
* Iterate backwards over list of given type, safe against removal
* of list entry.
*/
#define list_for_each_entry_safe_reverse(pos, n, head, member) \
- for (pos = list_entry((head)->prev, typeof(*pos), member), \
- n = list_entry(pos->member.prev, typeof(*pos), member); \
+ for (pos = list_last_entry(head, typeof(*pos), member), \
+ n = list_prev_entry(pos, member); \
&pos->member != (head); \
- pos = n, n = list_entry(n->member.prev, typeof(*n), member))
+ pos = n, n = list_prev_entry(n, member))
+
+/**
+ * list_safe_reset_next - reset a stale list_for_each_entry_safe loop
+ * @pos: the loop cursor used in the list_for_each_entry_safe loop
+ * @n: temporary storage used in list_for_each_entry_safe
+ * @member: the name of the list_head within the struct.
+ *
+ * list_safe_reset_next is not safe to use in general if the list may be
+ * modified concurrently (eg. the lock is dropped in the loop body). An
+ * exception to this is if the cursor element (pos) is pinned in the list,
+ * and list_safe_reset_next is called after re-taking the lock and before
+ * completing the current iteration of the loop body.
+ */
+#define list_safe_reset_next(pos, n, member) \
+ n = list_next_entry(pos, member)
#endif
--
1.8.4.2
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