Use non atomic unlock

Slub can use the non-atomic version to unlock because other flags will not
get modified with the lock held.

Signed-off-by: Nick Piggin <[e-mail]>
Acked-by: Christoph Lameter <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

mm/slub.c

···
 
 static __always_inline void slab_unlock(struct page *page)
 {
-	bit_spin_unlock(PG_locked, &page->flags);
+	__bit_spin_unlock(PG_locked, &page->flags);
 }
 
 static __always_inline int slab_trylock(struct page *page)