net: hns3: fix one incorrect value of page pool info when queried by debugfs

mainline inclusion
from mainline-v5.16-rc3
commit 9c147917
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I4M1HB
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9c1479174870

----------------------------------------------------------------------

Currently, when user queries page pool info by debugfs command
"cat page_pool_info", the cnt of allocated page for page pool may be
incorrect because of memory inconsistency problem caused by compiler
optimization.

So this patch uses READ_ONCE() to read value of pages_state_hold_cnt to
fix this problem.

Fixes: 850bfb91 ("net: hns3: debugfs add support dumping page pool info")
Signed-off-by: NHao Chen <chenhao288@hisilicon.com>
Signed-off-by: NGuangbin Huang <huangguangbin2@huawei.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>
Reviewed-by: NYongxin Li <liyongxin1@huawei.com>
Signed-off-by: NJunxin Chen <chenjunxin1@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/net/ethernet/hisilicon/hns3/hns3_debugfs.c

@@ -1081,7 +1081,8 @@ static void hns3_dump_page_pool_info(struct hns3_enet_ring *ring,
 	u32 j = 0;
 
 	sprintf(result[j++], "%u", index);
-	sprintf(result[j++], "%u", ring->page_pool->pages_state_hold_cnt);
+	sprintf(result[j++], "%u",
+		READ_ONCE(ring->page_pool->pages_state_hold_cnt));
 	sprintf(result[j++], "%u",
 		atomic_read(&ring->page_pool->pages_state_release_cnt));
 	sprintf(result[j++], "%u", ring->page_pool->p.pool_size);