[PATCH 19/23] vboxsf: Use a folio in vboxsf_write_end()

["Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>]

Because we have to kmap() the page before calling vboxsf_write(), we
can't entirely remove the use of struct page.  But we can eliminate some
uses of old APIs and remove some unnecessary calls to compound_head().

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
 fs/vboxsf/file.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/fs/vboxsf/file.c b/fs/vboxsf/file.c
index fdb4da24d662..029f106d56d9 100644
--- a/fs/vboxsf/file.c
+++ b/fs/vboxsf/file.c
@@ -302,16 +302,17 @@ static int vboxsf_write_end(struct file *file, struct address_space *mapping,
 			    loff_t pos, unsigned int len, unsigned int copied,
 			    struct page *page, void *fsdata)
 {
+	struct folio *folio = page_folio(page);
 	struct inode *inode = mapping->host;
 	struct vboxsf_handle *sf_handle = file->private_data;
-	unsigned int from = pos & ~PAGE_MASK;
+	size_t from = offset_in_folio(folio, pos);
 	u32 nwritten = len;
 	u8 *buf;
 	int err;
 
-	/* zero the stale part of the page if we did a short copy */
-	if (!PageUptodate(page) && copied < len)
-		zero_user(page, from + copied, len - copied);
+	/* zero the stale part of the folio if we did a short copy */
+	if (!folio_test_uptodate(folio) && copied < len)
+		folio_zero_range(folio, from + copied, len - copied);
 
 	buf = kmap(page);
 	err = vboxsf_write(sf_handle->root, sf_handle->handle,
@@ -326,16 +327,16 @@ static int vboxsf_write_end(struct file *file, struct address_space *mapping,
 	/* mtime changed */
 	VBOXSF_I(inode)->force_restat = 1;
 
-	if (!PageUptodate(page) && nwritten == PAGE_SIZE)
-		SetPageUptodate(page);
+	if (!folio_test_uptodate(folio) && nwritten == folio_size(folio))
+		folio_mark_uptodate(folio);
 
 	pos += nwritten;
 	if (pos > inode->i_size)
 		i_size_write(inode, pos);
 
 out:
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 
 	return nwritten;
 }
@@ -343,7 +344,7 @@ static int vboxsf_write_end(struct file *file, struct address_space *mapping,
 /*
  * Note simple_write_begin does not read the page from disk on partial writes
  * this is ok since vboxsf_write_end only writes the written parts of the
- * page and it does not call SetPageUptodate for partial writes.
+ * page and it does not call folio_mark_uptodate for partial writes.
  */
 const struct address_space_operations vboxsf_reg_aops = {
 	.read_folio = vboxsf_read_folio,
-- 
2.43.0