[PATCH 1/2] list: introduce a new cutting helper

[Christoph Hellwig]

On Thu, Jun 13, 2024 at 10:26:11AM +0530, Nilay Shroff wrote:
> I am wondering whether we really need the _rcu version of list_cut here?
> I think that @head could point to an _rcu protected list and that's true 
> for this patch. So there might be concurrent readers accessing @head using
> _rcu list-traversal primitives, such as list_for_each_entry_rcu().

Yes, I can't see how this works for a RCU lists without very careful
memory ordering.

Btw, another thing - the old vs new list ordering is reversed vs
list_splice*, which is a bit confusing (as are the parameter names
both for list_splice* and this new helper).  Can you switch them
around to match?