gfs2: convert gfs2_write_buf_to_page() to use a folio

Remove several folio->page->folio conversions.

Link: https://lkml.kernel.org/r/20231016201114.1928083-10-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

fs/gfs2/quota.c

@@ -749,7 +749,7 @@ static int gfs2_write_buf_to_page(struct gfs2_sbd *sdp, unsigned long index,
 	struct gfs2_inode *ip = GFS2_I(sdp->sd_quota_inode);
 	struct inode *inode = &ip->i_inode;
 	struct address_space *mapping = inode->i_mapping;
-	struct page *page;
+	struct folio *folio;
 	struct buffer_head *bh;
 	u64 blk;
 	unsigned bsize = sdp->sd_sb.sb_bsize, bnum = 0, boff = 0;
@@ -758,15 +758,15 @@ static int gfs2_write_buf_to_page(struct gfs2_sbd *sdp, unsigned long index,
 	blk = index << (PAGE_SHIFT - sdp->sd_sb.sb_bsize_shift);
 	boff = off % bsize;
 
-	page = grab_cache_page(mapping, index);
-	if (!page)
-		return -ENOMEM;
-	if (!page_has_buffers(page))
-		create_empty_buffers(page, bsize, 0);
+	folio = filemap_grab_folio(mapping, index);
+	if (IS_ERR(folio))
+		return PTR_ERR(folio);
+	bh = folio_buffers(folio);
+	if (!bh)
+		bh = folio_create_empty_buffers(folio, bsize, 0);
 
-	bh = page_buffers(page);
-	for(;;) {
-		/* Find the beginning block within the page */
+	for (;;) {
+		/* Find the beginning block within the folio */
 		if (pg_off >= ((bnum * bsize) + bsize)) {
 			bh = bh->b_this_page;
 			bnum++;
@@ -779,9 +779,10 @@ static int gfs2_write_buf_to_page(struct gfs2_sbd *sdp, unsigned long index,
 				goto unlock_out;
 			/* If it's a newly allocated disk block, zero it */
 			if (buffer_new(bh))
-				zero_user(page, bnum * bsize, bh->b_size);
+				folio_zero_range(folio, bnum * bsize,
+						bh->b_size);
 		}
-		if (PageUptodate(page))
+		if (folio_test_uptodate(folio))
 			set_buffer_uptodate(bh);
 		if (bh_read(bh, REQ_META | REQ_PRIO) < 0)
 			goto unlock_out;
@@ -797,17 +798,17 @@ static int gfs2_write_buf_to_page(struct gfs2_sbd *sdp, unsigned long index,
 		break;
 	}
 
-	/* Write to the page, now that we have setup the buffer(s) */
-	memcpy_to_page(page, off, buf, bytes);
-	flush_dcache_page(page);
-	unlock_page(page);
-	put_page(page);
+	/* Write to the folio, now that we have setup the buffer(s) */
+	memcpy_to_folio(folio, off, buf, bytes);
+	flush_dcache_folio(folio);
+	folio_unlock(folio);
+	folio_put(folio);
 
 	return 0;
 
 unlock_out:
-	unlock_page(page);
-	put_page(page);
+	folio_unlock(folio);
+	folio_put(folio);
 	return -EIO;
 }