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| author |   Ricardo Martinez <ricardo.martinez@linux.intel.com> | 2022-05-06 11:12:57 -0700 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2022-05-09 10:51:58 +0100 |
| commit | 2fbdf45d7d26361a0c3ec8833fd96edf0f5812da (patch) | |
| tree | 656bac038c34f0ba955ddb466d39d32cc0a9acde | |
| parent | Merge tag 'batadv-next-pullrequest-20220508' of git://git.open-mesh.org/linux-merge (diff) | |
| download | linux-dev-2fbdf45d7d26361a0c3ec8833fd96edf0f5812da.tar.xz linux-dev-2fbdf45d7d26361a0c3ec8833fd96edf0f5812da.zip | |
list: Add list_next_entry_circular() and list_prev_entry_circular()
Add macros to get the next or previous entries and wraparound if
needed. For example, calling list_next_entry_circular() on the last
element should return the first element in the list.
Signed-off-by: Ricardo Martinez <ricardo.martinez@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/list.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/include/linux/list.h b/include/linux/list.h index dd6c2041d09c..c147eeb2d39d 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -564,6 +564,19 @@ static inline void list_splice_tail_init(struct list_head *list, list_entry((pos)->member.next, typeof(*(pos)), member) /** + * list_next_entry_circular - get the next element in list + * @pos: the type * to cursor. + * @head: the list head to take the element from. + * @member: the name of the list_head within the struct. + * + * Wraparound if pos is the last element (return the first element). + * Note, that list is expected to be not empty. + */ +#define list_next_entry_circular(pos, head, member) \ + (list_is_last(&(pos)->member, head) ? \ + list_first_entry(head, typeof(*(pos)), member) : list_next_entry(pos, member)) + +/** * list_prev_entry - get the prev element in list * @pos: the type * to cursor * @member: the name of the list_head within the struct. @@ -572,6 +585,19 @@ static inline void list_splice_tail_init(struct list_head *list, list_entry((pos)->member.prev, typeof(*(pos)), member) /** + * list_prev_entry_circular - get the prev element in list + * @pos: the type * to cursor. + * @head: the list head to take the element from. + * @member: the name of the list_head within the struct. + * + * Wraparound if pos is the first element (return the last element). + * Note, that list is expected to be not empty. + */ +#define list_prev_entry_circular(pos, head, member) \ + (list_is_first(&(pos)->member, head) ? \ + list_last_entry(head, typeof(*(pos)), member) : list_prev_entry(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. |