block: Convert read_part_sector() to use a folio

This relatively straightforward converion saves a call to compound_head()
hidden inside put_page().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

block/partitions/check.h

@@ -24,13 +24,13 @@ struct parsed_partitions {
 };
 
 typedef struct {
-	struct page *v;
+	struct folio *v;
 } Sector;
 
 void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p);
 static inline void put_dev_sector(Sector p)
 {
-	put_page(p.v);
+	folio_put(p.v);
 }
 
 static inline void

block/partitions/core.c

@@ -705,19 +705,19 @@ EXPORT_SYMBOL_GPL(bdev_disk_changed);
 void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p)
 {
 	struct address_space *mapping = state->disk->part0->bd_inode->i_mapping;
-	struct page *page;
+	struct folio *folio;
 
 	if (n >= get_capacity(state->disk)) {
 		state->access_beyond_eod = true;
 		goto out;
 	}
 
-	page = read_mapping_page(mapping, n >> PAGE_SECTORS_SHIFT, NULL);
-	if (IS_ERR(page))
+	folio = read_mapping_folio(mapping, n >> PAGE_SECTORS_SHIFT, NULL);
+	if (IS_ERR(folio))
 		goto out;
 
-	p->v = page;
-	return page_address(page) + offset_in_page(n * SECTOR_SIZE);
+	p->v = folio;
+	return folio_address(folio) + offset_in_folio(folio, n * SECTOR_SIZE);
 out:
 	p->v = NULL;
 	return NULL;