nilfs2: get rid of nilfs_mapping_init()

After applying the lockdep warning fixes, nilfs_mapping_init() is no
longer used, so delete it.

Link: https://lkml.kernel.org/r/1647867427-30498-4-git-send-email-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hao Sun <sunhao.th@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: konis

fs/nilfs2/page.c

@@ -436,15 +436,6 @@ unsigned int nilfs_page_count_clean_buffers(struct page *page,
 	return nc;
 }
 
-void nilfs_mapping_init(struct address_space *mapping, struct inode *inode)
-{
-	mapping->host = inode;
-	mapping->flags = 0;
-	mapping_set_gfp_mask(mapping, GFP_NOFS);
-	mapping->private_data = NULL;
-	mapping->a_ops = &empty_aops;
-}
-
 /*
  * NILFS2 needs clear_page_dirty() in the following two cases:
  *

fs/nilfs2/page.h

@@ -43,7 +43,6 @@ int nilfs_copy_dirty_pages(struct address_space *, struct address_space *);
 void nilfs_copy_back_pages(struct address_space *, struct address_space *);
 void nilfs_clear_dirty_page(struct page *, bool);
 void nilfs_clear_dirty_pages(struct address_space *, bool);
-void nilfs_mapping_init(struct address_space *mapping, struct inode *inode);
 unsigned int nilfs_page_count_clean_buffers(struct page *, unsigned int,
 					    unsigned int);
 unsigned long nilfs_find_uncommitted_extent(struct inode *inode,