Byungchul Park <byungchul.p...@lge.com> writes: > On Mon, Feb 13, 2017 at 03:36:33PM +0800, Huang, Ying wrote: >> Byungchul Park <byungchul.p...@lge.com> writes: >> >> > Sometimes we have to dereference next field of llist node before entering >> > loop becasue the node might be deleted or the next field might be >> > modified within the loop. So this adds the safe version of llist_for_each, >> > that is, llist_for_each_safe. >> > >> > Signed-off-by: Byungchul Park <byungchul.p...@lge.com> >> > --- >> > include/linux/llist.h | 19 +++++++++++++++++++ >> > 1 file changed, 19 insertions(+) >> > >> > diff --git a/include/linux/llist.h b/include/linux/llist.h >> > index fd4ca0b..4c508a5 100644 >> > --- a/include/linux/llist.h >> > +++ b/include/linux/llist.h >> > @@ -105,6 +105,25 @@ static inline void init_llist_head(struct llist_head >> > *list) >> > for ((pos) = (node); pos; (pos) = (pos)->next) >> > >> > /** >> > + * llist_for_each_safe - iterate over some deleted entries of a lock-less >> > list >> > + * safe against removal of list entry >> > + * @pos: the &struct llist_node to use as a loop cursor >> > + * @n: another type * to use as temporary storage >> >> s/type */&struct llist_node/ > > Yes. > >> >> > + * @node: the first entry of deleted list entries >> > + * >> > + * In general, some entries of the lock-less list can be traversed >> > + * safely only after being deleted from list, so start with an entry >> > + * instead of list head. >> > + * >> > + * If being used on entries deleted from lock-less list directly, the >> > + * traverse order is from the newest to the oldest added entry. If >> > + * you want to traverse from the oldest to the newest, you must >> > + * reverse the order by yourself before traversing. >> > + */ >> > +#define llist_for_each_safe(pos, n, node) \ >> > + for ((pos) = (node); (pos) && ((n) = (pos)->next, true); (pos) = (n)) >> > + >> >> Following the style of other xxx_for_each_safe, >> >> #define llist_for_each_safe(pos, n, node) \ >> for (pos = (node), (pos && (n = pos->next)); pos; pos = n, n = >> pos->next) > > Do you think it should be modified? I think mine is simpler. No?
Personally I prefer the style of other xxx_for_each_safe(). Best Regards, Huang, Ying >> >> Best Regards, >> Huang, Ying >> >> > +/** >> > * llist_for_each_entry - iterate over some deleted entries of lock-less >> > list of given type >> > * @pos: the type * to use as a loop cursor. >> > * @node: the fist entry of deleted list entries.
