[PATCH 0/6] list: introduce list_last_entry_or_null()

[Jeff Liu <jeff.liu@xxxxxxxxxx>]

Hi Folks,

This patch is trying to introduce a new list helper to retrieve the
last entry or return NULL if the list is empty corresponding to it,
which is inspired by Jiri Pirko's list_first_entry_or_null().

With this trivial helper, we could get a little benefit to simplify
the code logic of xfs_ail_max() and make the code looks a bit more
consistent with xfs_ail_min() which has already been simplified
via list_first_entry_or_null().

Moreover, as a per simple grep against fs as well as driver's tree,
I think there are some other places could make use of it for similar
purpose, here I spread this helper over some file systems as well.

Any comments are welcome!

Thanks,
-Jeff