The patch titled
Subject: list: introduce list_is_head() helper and re-use it in list.h
has been added to the -mm tree. Its filename is
list-introduce-list_is_head-helper-and-re-use-it-in-listh.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/list-introduce-list_is_head-helper-and-re-use-it-in-listh.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/list-introduce-list_is_head-helper-and-re-use-it-in-listh.patch
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------------------------------------------------------
From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Subject: list: introduce list_is_head() helper and re-use it in list.h
Introduce list_is_head() in the similar (*) way as it's done for
list_entry_is_head(). Make use of it in the list.h.
*) it's done as inliner and not a macro to be aligned with other
list_is_*() APIs; while at it, make all three to have the same
style.
Link: https://lkml.kernel.org/r/20211201141824.81400-1-andriy.shevchenko@xxxxxxxxxxxxxxx
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/list.h | 36 ++++++++++++++++++++++--------------
1 file changed, 22 insertions(+), 14 deletions(-)
--- a/include/linux/list.h~list-introduce-list_is_head-helper-and-re-use-it-in-listh
+++ a/include/linux/list.h
@@ -258,8 +258,7 @@ static inline void list_bulk_move_tail(s
* @list: the entry to test
* @head: the head of the list
*/
-static inline int list_is_first(const struct list_head *list,
- const struct list_head *head)
+static inline int list_is_first(const struct list_head *list, const struct list_head *head)
{
return list->prev == head;
}
@@ -269,13 +268,22 @@ static inline int list_is_first(const st
* @list: the entry to test
* @head: the head of the list
*/
-static inline int list_is_last(const struct list_head *list,
- const struct list_head *head)
+static inline int list_is_last(const struct list_head *list, const struct list_head *head)
{
return list->next == head;
}
/**
+ * list_is_head - tests whether @list is the list @head
+ * @list: the entry to test
+ * @head: the head of the list
+ */
+static inline int list_is_head(const struct list_head *list, const struct list_head *head)
+{
+ return list == head;
+}
+
+/**
* list_empty - tests whether a list is empty
* @head: the list to test.
*/
@@ -318,7 +326,7 @@ static inline void list_del_init_careful
static inline int list_empty_careful(const struct list_head *head)
{
struct list_head *next = smp_load_acquire(&head->next);
- return (next == head) && (next == head->prev);
+ return list_is_head(next, head) && (next == head->prev);
}
/**
@@ -393,10 +401,9 @@ static inline void list_cut_position(str
{
if (list_empty(head))
return;
- if (list_is_singular(head) &&
- (head->next != entry && head != entry))
+ if (list_is_singular(head) && !list_is_head(entry, head) && (entry != head->next))
return;
- if (entry == head)
+ if (list_is_head(entry, head))
INIT_LIST_HEAD(list);
else
__list_cut_position(list, head, entry);
@@ -570,7 +577,7 @@ static inline void list_splice_tail_init
* @head: the head for your list.
*/
#define list_for_each(pos, head) \
- for (pos = (head)->next; pos != (head); pos = pos->next)
+ for (pos = (head)->next; !list_is_head(pos, (head)); pos = pos->next)
/**
* list_for_each_continue - continue iteration over a list
@@ -580,7 +587,7 @@ static inline void list_splice_tail_init
* Continue to iterate over a list, continuing after the current position.
*/
#define list_for_each_continue(pos, head) \
- for (pos = pos->next; pos != (head); pos = pos->next)
+ for (pos = pos->next; !list_is_head(pos, (head)); pos = pos->next)
/**
* list_for_each_prev - iterate over a list backwards
@@ -588,7 +595,7 @@ static inline void list_splice_tail_init
* @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; !list_is_head(pos, (head)); pos = pos->prev)
/**
* list_for_each_safe - iterate over a list safe against removal of list entry
@@ -597,8 +604,9 @@ static inline void list_splice_tail_init
* @head: the head for your list.
*/
#define list_for_each_safe(pos, n, head) \
- for (pos = (head)->next, n = pos->next; pos != (head); \
- pos = n, n = pos->next)
+ for (pos = (head)->next, n = pos->next; \
+ !list_is_head(pos, (head)); \
+ pos = n, n = pos->next)
/**
* list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
@@ -608,7 +616,7 @@ static inline void list_splice_tail_init
*/
#define list_for_each_prev_safe(pos, n, head) \
for (pos = (head)->prev, n = pos->prev; \
- pos != (head); \
+ !list_is_head(pos, (head)); \
pos = n, n = pos->prev)
/**
_
Patches currently in -mm which might be from andriy.shevchenko@xxxxxxxxxxxxxxx are
list-introduce-list_is_head-helper-and-re-use-it-in-listh.patch
