mm/page_ref: use page_ref helper instead of direct modification of _count

page_reference manipulation functions are introduced to track down
reference count change of the page.  Use it instead of direct
modification of _count.

Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Sunil Goutham <sgoutham@cavium.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
index 06b819d..0ff8e60 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_queues.c
@@ -23,7 +23,7 @@
 	if (!nic->rb_pageref || !nic->rb_page)
 		return;
 
-	atomic_add(nic->rb_pageref, &nic->rb_page->_count);
+	page_ref_add(nic->rb_page, nic->rb_pageref);
 	nic->rb_pageref = 0;
 }
 
diff --git a/drivers/net/ethernet/qlogic/qede/qede_main.c b/drivers/net/ethernet/qlogic/qede/qede_main.c
index 8114541..3aabfc0 100644
--- a/drivers/net/ethernet/qlogic/qede/qede_main.c
+++ b/drivers/net/ethernet/qlogic/qede/qede_main.c
@@ -920,7 +920,7 @@
 		 * network stack to take the ownership of the page
 		 * which can be recycled multiple times by the driver.
 		 */
-		atomic_inc(&curr_cons->data->_count);
+		page_ref_inc(curr_cons->data);
 		qede_reuse_page(edev, rxq, curr_cons);
 	}
 
diff --git a/mm/filemap.c b/mm/filemap.c
index 182b218..0169033 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -213,7 +213,7 @@
 			 * some other bad page check should catch it later.
 			 */
 			page_mapcount_reset(page);
-			atomic_sub(mapcount, &page->_count);
+			page_ref_sub(page, mapcount);
 		}
 	}
 
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 219bd19..4e809e9 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -651,7 +651,7 @@
 	struct skb_shared_info *sh = skb_shinfo(skb);
 	int page_offset;
 
-	atomic_inc(&page->_count);
+	page_ref_inc(page);
 	page_offset = ptr - page_address(page);
 	skb_add_rx_frag(skb, sh->nr_frags, page, page_offset, len, size);
 }