| Message ID | 20130705204129.GB15943@logfs.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Jul 5, 2013 at 9:41 PM, Jörn Engel <joern@logfs.org> wrote: > I have seen a lot of boilerplate code that either follows the pattern of > while (!list_empty(head)) { > pos = list_entry(head->next, struct foo, list); > list_del(pos->list); > ... > } > or some variant thereof. > > With this patch in, people can use > list_del_each_entry(pos, head, list) { > ... > } > > The patch also adds a list_del_each variant, even though I have > only found a single user for that one so far. > > Signed-off-by: Joern Engel <joern@logfs.org> > --- > include/linux/list.h | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/include/linux/list.h b/include/linux/list.h > index 6a1f8df..ab39c7d 100644 > --- a/include/linux/list.h > +++ b/include/linux/list.h > @@ -557,6 +557,24 @@ static inline void list_splice_tail_init(struct list_head *list, > #define list_safe_reset_next(pos, n, member) \ > n = list_entry(pos->member.next, typeof(*pos), member) > > +/** > + * list_del_each - removes an entry from the list until it is empty > + * @pos: the &struct list_head to use as a loop cursor. > + * @head: the head of your list. > + */ > +#define list_del_each(pos, head) \ > + while (list_empty(head) ? 0 : (pos = (head)->next, list_del(pos), 1)) > + > +/** > + * list_del_each_entry - removes an entry from the list until it is empty > + * @pos: the type * to use as loop cursor. > + * @head: the head of your list. > + * @member: the name of the list_struct within the struct > + */ > +#define list_del_each_entry(pos, head, member) \ > + while (list_empty(head) && (pos = list_first_entry((head), \ > + typeof(*pos), member), list_del((head)->next), 1)) > + Shouldn't it be while (!list_empty(head) ... ? (not operator addition) thanks > /* > * Double linked lists with a single pointer list head. > * Mostly useful for hash tables where the two pointer list head is > -- > 1.7.10.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Filipe David Manana, "Reasonable men adapt themselves to the world. Unreasonable men adapt the world to themselves. That's why all progress depends on unreasonable men." -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, 5 July 2013 23:38:01 +0100, Filipe David Manana wrote: > > > +#define list_del_each_entry(pos, head, member) \ > > + while (list_empty(head) && (pos = list_first_entry((head), \ > > + typeof(*pos), member), list_del((head)->next), 1)) > > + > > Shouldn't it be while (!list_empty(head) ... ? > (not operator addition) Obviously! Now where is that brown paperbag... Will resend in a few days, including the _init variants dchinner asked for. Jörn -- Computer system analysis is like child-rearing; you can do grievous damage, but you cannot ensure success." -- Tom DeMarco -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/list.h b/include/linux/list.h index 6a1f8df..ab39c7d 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -557,6 +557,24 @@ static inline void list_splice_tail_init(struct list_head *list, #define list_safe_reset_next(pos, n, member) \ n = list_entry(pos->member.next, typeof(*pos), member) +/** + * list_del_each - removes an entry from the list until it is empty + * @pos: the &struct list_head to use as a loop cursor. + * @head: the head of your list. + */ +#define list_del_each(pos, head) \ + while (list_empty(head) ? 0 : (pos = (head)->next, list_del(pos), 1)) + +/** + * list_del_each_entry - removes an entry from the list until it is empty + * @pos: the type * to use as loop cursor. + * @head: the head of your list. + * @member: the name of the list_struct within the struct + */ +#define list_del_each_entry(pos, head, member) \ + while (list_empty(head) && (pos = list_first_entry((head), \ + typeof(*pos), member), list_del((head)->next), 1)) + /* * Double linked lists with a single pointer list head. * Mostly useful for hash tables where the two pointer list head is
I have seen a lot of boilerplate code that either follows the pattern of while (!list_empty(head)) { pos = list_entry(head->next, struct foo, list); list_del(pos->list); ... } or some variant thereof. With this patch in, people can use list_del_each_entry(pos, head, list) { ... } The patch also adds a list_del_each variant, even though I have only found a single user for that one so far. Signed-off-by: Joern Engel <joern@logfs.org> --- include/linux/list.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)