On Thu, Jan 13, 2022 at 06:06:15PM -0700, Ricardo Martinez wrote: > 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. FWIW, Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> > Signed-off-by: Ricardo Martinez <ricardo.martinez@xxxxxxxxxxxxxxx> > --- > include/linux/list.h | 26 ++++++++++++++++++++++++++ > 1 file changed, 26 insertions(+) > > 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 > @@ -563,6 +563,19 @@ static inline void list_splice_tail_init(struct list_head *list, > #define list_next_entry(pos, member) \ > 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 > @@ -571,6 +584,19 @@ static inline void list_splice_tail_init(struct list_head *list, > #define list_prev_entry(pos, member) \ > 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. > -- > 2.17.1 > -- With Best Regards, Andy Shevchenko
