ksm: add the ksm prefix to the names of the ksm private structures

In order to prevent the name of the private structure of ksm from being
the same as the name of the common structure used in subsequent patches,
prefix their names with ksm in advance.

Link: https://lkml.kernel.org/r/20220831031951.43152-5-zhengqi.arch@bytedance.comSigned-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/mm/ksm.rst

@@ -26,7 +26,7 @@ tree.
 
 If a KSM page is shared between less than ``max_page_sharing`` VMAs,
 the node of the stable tree that represents such KSM page points to a
-list of struct rmap_item and the ``page->mapping`` of the
+list of struct ksm_rmap_item and the ``page->mapping`` of the
 KSM page points to the stable tree node.
 
 When the sharing passes this threshold, KSM adds a second dimension to