fs: Change the type of filler_t

By making filler_t the same as read_folio, we can use the same function
for both in gfs2.  We can push the use of folios down one more level
in jffs2 and nfs.  We also increase type safety for future users of the
various read_cache_page() family of functions by forcing the parameter
to be a pointer to struct file (or NULL).

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>

3 files changed, 6 insertions, 7 deletions

diff --git a/fs/jffs2/file.c b/fs/jffs2/file.c
index 492fb2da0403..ba86acbe12d3 100644
--- a/fs/jffs2/file.c
+++ b/fs/jffs2/file.c
@@ -110,21 +110,20 @@ static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
 	return ret;
 }
 
-int jffs2_do_readpage_unlock(void *data, struct page *pg)
+int __jffs2_read_folio(struct file *file, struct folio *folio)
 {
-	int ret = jffs2_do_readpage_nolock(pg->mapping->host, pg);
-	unlock_page(pg);
+	int ret = jffs2_do_readpage_nolock(folio->mapping->host, &folio->page);
+	folio_unlock(folio);
 	return ret;
 }
 
-
 static int jffs2_read_folio(struct file *file, struct folio *folio)
 {
 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host);
 	int ret;
 
 	mutex_lock(&f->sem);
-	ret = jffs2_do_readpage_unlock(file, &folio->page);
+	ret = __jffs2_read_folio(file, folio);
 	mutex_unlock(&f->sem);
 	return ret;
 }
diff --git a/fs/jffs2/gc.c b/fs/jffs2/gc.c
index a53bac7569b6..5c6602f3c189 100644
--- a/fs/jffs2/gc.c
+++ b/fs/jffs2/gc.c
@@ -1327,7 +1327,7 @@ static int jffs2_garbage_collect_dnode(struct jffs2_sb_info *c, struct jffs2_era
 	 * trying to write out, read_cache_page() will not deadlock. */
 	mutex_unlock(&f->sem);
 	page = read_cache_page(inode->i_mapping, start >> PAGE_SHIFT,
-			       jffs2_do_readpage_unlock, NULL);
+			       __jffs2_read_folio, NULL);
 	if (IS_ERR(page)) {
 		pr_warn("read_cache_page() returned error: %ld\n",
 			PTR_ERR(page));
diff --git a/fs/jffs2/os-linux.h b/fs/jffs2/os-linux.h
index 173eccac691d..921d782583d6 100644
--- a/fs/jffs2/os-linux.h
+++ b/fs/jffs2/os-linux.h
@@ -155,7 +155,7 @@ extern const struct file_operations jffs2_file_operations;
 extern const struct inode_operations jffs2_file_inode_operations;
 extern const struct address_space_operations jffs2_file_address_operations;
 int jffs2_fsync(struct file *, loff_t, loff_t, int);
-int jffs2_do_readpage_unlock(void *data, struct page *pg);
+int __jffs2_read_folio(struct file *file, struct folio *folio);
 
 /* ioctl.c */
 long jffs2_ioctl(struct file *, unsigned int, unsigned long);