lkml.org 
[lkml]   [2021]   [Dec]   [1]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v1 1/1] list: Introduce list_is_head() helper and re-use it in list.h
Date
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.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
include/linux/list.h | 36 ++++++++++++++++++++++--------------
1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/include/linux/list.h b/include/linux/list.h
index 6636fc07f918..dd6c2041d09c 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -258,8 +258,7 @@ static inline void list_bulk_move_tail(struct list_head *head,
* @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;
}
@@ -269,12 +268,21 @@ static inline int list_is_first(const struct list_head *list,
* @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(struct list_head *entry)
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(struct list_head *list,
{
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(struct list_head *list,
* @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(struct list_head *list,
* 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(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; !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(struct list_head *list,
* @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(struct list_head *list,
*/
#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)

/**
--
2.33.0
\
 
 \ /
  Last update: 2021-12-01 15:20    [W:0.037 / U:0.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site