mm/workingset: remove unused @mapping argument in workingset_eviction()

workingset_eviction() doesn't use and never did use the @mapping
argument.  Remove it.

Link: http://lkml.kernel.org/r/20190228083329.31892-1-aryabinin@virtuozzo.comSigned-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Rik van Riel <riel@surriel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/swap.h

@@ -307,7 +307,7 @@ struct vma_swap_readahead {
 };
 
 /* linux/mm/workingset.c */
-void *workingset_eviction(struct address_space *mapping, struct page *page);
+void *workingset_eviction(struct page *page);
 void workingset_refault(struct page *page, void *shadow);
 void workingset_activation(struct page *page);
 

mm/vmscan.c

@@ -952,7 +952,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
 		 */
 		if (reclaimed && page_is_file_cache(page) &&
 		    !mapping_exiting(mapping) && !dax_mapping(mapping))
-			shadow = workingset_eviction(mapping, page);
+			shadow = workingset_eviction(page);
 		__delete_from_page_cache(page, shadow);
 		xa_unlock_irqrestore(&mapping->i_pages, flags);
 

mm/workingset.c

@@ -215,13 +215,12 @@ static void unpack_shadow(void *shadow, int *memcgidp, pg_data_t **pgdat,
 
 /**
  * workingset_eviction - note the eviction of a page from memory
- * @mapping: address space the page was backing
  * @page: the page being evicted
  *
- * Returns a shadow entry to be stored in @mapping->i_pages in place
+ * Returns a shadow entry to be stored in @page->mapping->i_pages in place
  * of the evicted @page so that a later refault can be detected.
  */
-void *workingset_eviction(struct address_space *mapping, struct page *page)
+void *workingset_eviction(struct page *page)
 {
 	struct pglist_data *pgdat = page_pgdat(page);
 	struct mem_cgroup *memcg = page_memcg(page);