mm: cleanup descriptions of filler arg

The often-NULL data arg to read_cache_page() and read_mapping_page()
functions is misdescribed as "destination for read data": no, it's the
first arg to the filler function, often struct file * to ->readpage().

Satisfy checkpatch.pl on those filler prototypes, and tidy up the
declarations in linux/pagemap.h.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 8e38d4c..cfaaa69 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -255,26 +255,24 @@
 extern struct page * grab_cache_page_nowait(struct address_space *mapping,
 				pgoff_t index);
 extern struct page * read_cache_page_async(struct address_space *mapping,
-				pgoff_t index, filler_t *filler,
-				void *data);
+				pgoff_t index, filler_t *filler, void *data);
 extern struct page * read_cache_page(struct address_space *mapping,
-				pgoff_t index, filler_t *filler,
-				void *data);
+				pgoff_t index, filler_t *filler, void *data);
 extern struct page * read_cache_page_gfp(struct address_space *mapping,
 				pgoff_t index, gfp_t gfp_mask);
 extern int read_cache_pages(struct address_space *mapping,
 		struct list_head *pages, filler_t *filler, void *data);
 
 static inline struct page *read_mapping_page_async(
-						struct address_space *mapping,
-						     pgoff_t index, void *data)
+				struct address_space *mapping,
+				pgoff_t index, void *data)
 {
 	filler_t *filler = (filler_t *)mapping->a_ops->readpage;
 	return read_cache_page_async(mapping, index, filler, data);
 }
 
 static inline struct page *read_mapping_page(struct address_space *mapping,
-					     pgoff_t index, void *data)
+				pgoff_t index, void *data)
 {
 	filler_t *filler = (filler_t *)mapping->a_ops->readpage;
 	return read_cache_page(mapping, index, filler, data);