iomap: Convert iomap_page_create to take a folio

This function already assumed it was being passed a head page, so
just formalise that.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/iomap/buffered-io.c

@@ -42,11 +42,10 @@ static inline struct iomap_page *to_iomap_page(struct folio *folio)
 static struct bio_set iomap_ioend_bioset;
 
 static struct iomap_page *
-iomap_page_create(struct inode *inode, struct page *page)
+iomap_page_create(struct inode *inode, struct folio *folio)
 {
-	struct folio *folio = page_folio(page);
 	struct iomap_page *iop = to_iomap_page(folio);
-	unsigned int nr_blocks = i_blocks_per_page(inode, page);
+	unsigned int nr_blocks = i_blocks_per_folio(inode, folio);
 
 	if (iop || nr_blocks <= 1)
 		return iop;
@@ -54,9 +53,9 @@ iomap_page_create(struct inode *inode, struct page *page)
 	iop = kzalloc(struct_size(iop, uptodate, BITS_TO_LONGS(nr_blocks)),
 			GFP_NOFS | __GFP_NOFAIL);
 	spin_lock_init(&iop->uptodate_lock);
-	if (PageUptodate(page))
+	if (folio_test_uptodate(folio))
 		bitmap_fill(iop->uptodate, nr_blocks);
-	attach_page_private(page, iop);
+	folio_attach_private(folio, iop);
 	return iop;
 }
 
@@ -213,6 +212,7 @@ struct iomap_readpage_ctx {
 static int iomap_read_inline_data(const struct iomap_iter *iter,
 		struct page *page)
 {
+	struct folio *folio = page_folio(page);
 	const struct iomap *iomap = iomap_iter_srcmap(iter);
 	size_t size = i_size_read(iter->inode) - iomap->offset;
 	size_t poff = offset_in_page(iomap->offset);
@@ -229,7 +229,7 @@ static int iomap_read_inline_data(const struct iomap_iter *iter,
 	if (WARN_ON_ONCE(size > iomap->length))
 		return -EIO;
 	if (poff > 0)
-		iomap_page_create(iter->inode, page);
+		iomap_page_create(iter->inode, folio);
 
 	addr = kmap_local_page(page) + poff;
 	memcpy(addr, iomap->inline_data, size);
@@ -256,6 +256,7 @@ static loff_t iomap_readpage_iter(const struct iomap_iter *iter,
 	loff_t pos = iter->pos + offset;
 	loff_t length = iomap_length(iter) - offset;
 	struct page *page = ctx->cur_page;
+	struct folio *folio = page_folio(page);
 	struct iomap_page *iop;
 	loff_t orig_pos = pos;
 	unsigned poff, plen;
@@ -265,7 +266,7 @@ static loff_t iomap_readpage_iter(const struct iomap_iter *iter,
 		return iomap_read_inline_data(iter, page);
 
 	/* zero post-eof blocks as the page may be mapped */
-	iop = iomap_page_create(iter->inode, page);
+	iop = iomap_page_create(iter->inode, folio);
 	iomap_adjust_read_range(iter->inode, iop, &pos, length, &poff, &plen);
 	if (plen == 0)
 		goto done;
@@ -547,8 +548,9 @@ iomap_read_page_sync(loff_t block_start, struct page *page, unsigned poff,
 static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
 		unsigned len, struct page *page)
 {
+	struct folio *folio = page_folio(page);
 	const struct iomap *srcmap = iomap_iter_srcmap(iter);
-	struct iomap_page *iop = iomap_page_create(iter->inode, page);
+	struct iomap_page *iop = iomap_page_create(iter->inode, folio);
 	loff_t block_size = i_blocksize(iter->inode);
 	loff_t block_start = round_down(pos, block_size);
 	loff_t block_end = round_up(pos + len, block_size);
@@ -1296,7 +1298,8 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc,
 		struct writeback_control *wbc, struct inode *inode,
 		struct page *page, u64 end_offset)
 {
-	struct iomap_page *iop = iomap_page_create(inode, page);
+	struct folio *folio = page_folio(page);
+	struct iomap_page *iop = iomap_page_create(inode, folio);
 	struct iomap_ioend *ioend, *next;
 	unsigned len = i_blocksize(inode);
 	u64 file_offset; /* file offset of page */