mm/filemap: remove unused parameter and change to void type for replace_page_cache_page()

Since commit 74d609585d ("page cache: Add and replace pages using the
XArray") was merged, the replace_page_cache_page() can not fail and always
return 0, we can remove the redundant return value and void it.  Moreover
remove the unused gfp_mask.

Link: https://lkml.kernel.org/r/609c30e5274ba15d8b90c872fd0d8ac437a9b2bb.1610071401.git.baolin.wang@linux.alibaba.com
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/fuse/dev.c

@@ -844,11 +844,7 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 	if (WARN_ON(PageMlocked(oldpage)))
 		goto out_fallback_unlock;
 
-	err = replace_page_cache_page(oldpage, newpage, GFP_KERNEL);
-	if (err) {
-		unlock_page(newpage);
-		goto out_put_old;
-	}
+	replace_page_cache_page(oldpage, newpage);
 
 	get_page(newpage);
 

include/linux/pagemap.h

@@ -757,7 +757,7 @@ int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
 				pgoff_t index, gfp_t gfp_mask);
 extern void delete_from_page_cache(struct page *page);
 extern void __delete_from_page_cache(struct page *page, void *shadow);
-int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask);
+void replace_page_cache_page(struct page *old, struct page *new);
 void delete_from_page_cache_batch(struct address_space *mapping,
 				  struct pagevec *pvec);
 

mm/filemap.c

@@ -777,7 +777,6 @@ EXPORT_SYMBOL(file_write_and_wait_range);
  * replace_page_cache_page - replace a pagecache page with a new one
  * @old:	page to be replaced
  * @new:	page to replace with
- * @gfp_mask:	allocation mode
  *
  * This function replaces a page in the pagecache with a new one.  On
  * success it acquires the pagecache reference for the new page and
@@ -786,10 +785,8 @@ EXPORT_SYMBOL(file_write_and_wait_range);
  * caller must do that.
  *
  * The remove + add is atomic.  This function cannot fail.
- *
- * Return: %0
  */
-int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
+void replace_page_cache_page(struct page *old, struct page *new)
 {
 	struct address_space *mapping = old->mapping;
 	void (*freepage)(struct page *) = mapping->a_ops->freepage;
@@ -824,8 +821,6 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
 	if (freepage)
 		freepage(old);
 	put_page(old);
-
-	return 0;
 }
 EXPORT_SYMBOL_GPL(replace_page_cache_page);