xskmap: Move non-standard list manipulation to helper

Add a helper in list.h for the non-standard way of clearing a list that is
used in xskmap. This makes it easier to reuse it in the other map types,
and also makes sure this usage is not forgotten in any list refactorings in
the future.

Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Toke Høiland-Jørgensen 2019-06-28 11:12:34 +02:00 committed by Daniel Borkmann
parent 2d6dbb9a65
commit c8af5cd75e
2 changed files with 15 additions and 2 deletions

View File

@ -106,6 +106,20 @@ static inline void __list_del(struct list_head * prev, struct list_head * next)
WRITE_ONCE(prev->next, next);
}
/*
* Delete a list entry and clear the 'prev' pointer.
*
* This is a special-purpose list clearing method used in the networking code
* for lists allocated as per-cpu, where we don't want to incur the extra
* WRITE_ONCE() overhead of a regular list_del_init(). The code that uses this
* needs to check the node 'prev' pointer instead of calling list_empty().
*/
static inline void __list_del_clearprev(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
entry->prev = NULL;
}
/**
* list_del - deletes entry from list.
* @entry: the element to delete from the list.

View File

@ -145,8 +145,7 @@ void __xsk_map_flush(struct bpf_map *map)
list_for_each_entry_safe(xs, tmp, flush_list, flush_node) {
xsk_flush(xs);
__list_del(xs->flush_node.prev, xs->flush_node.next);
xs->flush_node.prev = NULL;
__list_del_clearprev(&xs->flush_node);
}
}