Hello, Waiman. On Mon, Oct 03, 2022 at 11:44:57AM -0400, Waiman Long wrote: > The lock-less list API is useful for dealing with list in a lock-less > manner. However, one of the drawback of the current API is that there > is not an easy way to determine if an entry has already been put into a > lock-less list. This has to be tracked externally and the tracking will > not be atomic unless some external synchronization logic is in place. > > This patch introduces a new variant of the lock-less list terminated > by a sentinel node instead of by NULL. The function names start with > "sllist" instead of "llist". The advantage of this scheme is that we > can atomically determine if an entry has been put into a lock-less > list by looking at the next pointer of the llist_node. Of course, the > callers must clear the next pointer when an entry is removed from the > lockless list. This is done automatically when the sllist_for_each_safe > or sllist_for_each_entry_safe iteraters are used. The non-safe versions > of sllist iterator are not provided. Any chance we can add sentinel to the existing llist instead of creating a new variant? There's no real downside to always using sentinel, right? Thanks. -- tejun
