tree 4efdedeabd066e15a542b28f21a47731c5323b5b
parent 58d6ea3085f2e53714810a513c61629f6d2be0a6
author Matthew Wilcox <willy@infradead.org> 1510346095 -0500
committer Matthew Wilcox <willy@infradead.org> 1540133158 -0400

xarray: Add XArray conditional store operations

Like cmpxchg(), xa_cmpxchg will only store to the index if the current
entry matches the old entry.  It returns the current entry, which is
usually more useful than the errno returned by radix_tree_insert().
For the users who really only want the errno, the xa_insert() wrapper
provides a more convenient calling convention.

Signed-off-by: Matthew Wilcox <willy@infradead.org>