udf: Move udf_adinicb_readpage() to inode.c

udf_adinicb_readpage() is only called from aops functions, move it to
the same file as its callers and also drop the stale comment -
invalidate_lock is protecting us against races with truncate.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/udf/file.c

@@ -38,25 +38,6 @@
 #include "udf_i.h"
 #include "udf_sb.h"
 
-void udf_adinicb_readpage(struct page *page)
-{
-	struct inode *inode = page->mapping->host;
-	char *kaddr;
-	struct udf_inode_info *iinfo = UDF_I(inode);
-	loff_t isize = i_size_read(inode);
-
-	/*
-	 * We have to be careful here as truncate can change i_size under us.
-	 * So just sample it once and use the same value everywhere.
-	 */
-	kaddr = kmap_atomic(page);
-	memcpy(kaddr, iinfo->i_data + iinfo->i_lenEAttr, isize);
-	memset(kaddr + isize, 0, PAGE_SIZE - isize);
-	flush_dcache_page(page);
-	SetPageUptodate(page);
-	kunmap_atomic(kaddr);
-}
-
 static vm_fault_t udf_page_mkwrite(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;

fs/udf/inode.c

@@ -215,6 +215,21 @@ static int udf_writepages(struct address_space *mapping,
 	return write_cache_pages(mapping, wbc, udf_adinicb_writepage, NULL);
 }
 
+static void udf_adinicb_readpage(struct page *page)
+{
+	struct inode *inode = page->mapping->host;
+	char *kaddr;
+	struct udf_inode_info *iinfo = UDF_I(inode);
+	loff_t isize = i_size_read(inode);
+
+	kaddr = kmap_atomic(page);
+	memcpy(kaddr, iinfo->i_data + iinfo->i_lenEAttr, isize);
+	memset(kaddr + isize, 0, PAGE_SIZE - isize);
+	flush_dcache_page(page);
+	SetPageUptodate(page);
+	kunmap_atomic(kaddr);
+}
+
 static int udf_read_folio(struct file *file, struct folio *folio)
 {
 	struct udf_inode_info *iinfo = UDF_I(file_inode(file));

fs/udf/udfdecl.h

@@ -137,7 +137,6 @@ static inline unsigned int udf_dir_entry_len(struct fileIdentDesc *cfi)
 
 /* file.c */
 extern long udf_ioctl(struct file *, unsigned int, unsigned long);
-void udf_adinicb_readpage(struct page *page);
 
 /* inode.c */
 extern struct inode *__udf_iget(struct super_block *, struct kernel_lb_addr *,