mm/page_io: convert bio_associate_blkg_from_page() to take in a folio

Convert bio_associate_blkg_from_page() to take in a folio. We can remove
two implicit calls to compound_head() by taking in a folio.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: ZhangPeng <[email protected]>
Reviewed-by: Matthew Wilcox (Oracle) <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Nanyong Sun <[email protected]>
Cc: Sidhartha Kumar <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: ZhangPeng

mm/page_io.c

@@ -215,12 +215,12 @@ static inline void count_swpout_vm_event(struct folio *folio)
 }
 
 #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
-static void bio_associate_blkg_from_page(struct bio *bio, struct page *page)
+static void bio_associate_blkg_from_page(struct bio *bio, struct folio *folio)
 {
 	struct cgroup_subsys_state *css;
 	struct mem_cgroup *memcg;
 
-	memcg = page_memcg(page);
+	memcg = folio_memcg(folio);
 	if (!memcg)
 		return;
 
@@ -230,7 +230,7 @@ static void bio_associate_blkg_from_page(struct bio *bio, struct page *page)
 	rcu_read_unlock();
 }
 #else
-#define bio_associate_blkg_from_page(bio, page)		do { } while (0)
+#define bio_associate_blkg_from_page(bio, folio)		do { } while (0)
 #endif /* CONFIG_MEMCG && CONFIG_BLK_CGROUP */
 
 struct swap_iocb {
@@ -338,7 +338,7 @@ static void swap_writepage_bdev_sync(struct page *page,
 	bio.bi_iter.bi_sector = swap_page_sector(page);
 	__bio_add_page(&bio, page, thp_size(page), 0);
 
-	bio_associate_blkg_from_page(&bio, page);
+	bio_associate_blkg_from_page(&bio, folio);
 	count_swpout_vm_event(folio);
 
 	folio_start_writeback(folio);
@@ -361,7 +361,7 @@ static void swap_writepage_bdev_async(struct page *page,
 	bio->bi_end_io = end_swap_bio_write;
 	__bio_add_page(bio, page, thp_size(page), 0);
 
-	bio_associate_blkg_from_page(bio, page);
+	bio_associate_blkg_from_page(bio, folio);
 	count_swpout_vm_event(folio);
 	folio_start_writeback(folio);
 	folio_unlock(folio);