The lockdep annotations for dev_uc_unsync() and dev_mc_unsync()
are not easy to understand, so add some comments to explain
why they are correct.
Similar for the rest netif_addr_lock_bh() cases, they don't
need nested version.
Cc: Taehee Yoo <ap420...@gmail.com>
Cc: Dmitry Vyukov <dvyu...@google.com>
Signed-off-by: Cong Wang <xiyou.wangc...@gmail.com>
---
net/core/dev_addr_lists.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/net/core/dev_addr_lists.c b/net/core/dev_addr_lists.c
index 6393ba930097..54cd568e7c2f 100644
--- a/net/core/dev_addr_lists.c
+++ b/net/core/dev_addr_lists.c
@@ -690,6 +690,15 @@ void dev_uc_unsync(struct net_device *to, struct
net_device *from)
if (to->addr_len != from->addr_len)
return;
+ /* netif_addr_lock_bh() uses lockdep subclass 0, this is okay for two
+ * reasons:
+ * 1) This is always called without any addr_list_lock, so as the
+ * outermost one here, it must be 0.
+ * 2) This is called by some callers after unlinking the upper device,
+ * so the dev->lower_level becomes 1 again.
+ * Therefore, the subclass for 'from' is 0, for 'to' is either 1 or
+ * larger.
+ */
netif_addr_lock_bh(from);
netif_addr_lock_nested(to);
__hw_addr_unsync(&to->uc, &from->uc, to->addr_len);
@@ -911,6 +920,7 @@ void dev_mc_unsync(struct net_device *to, struct net_device
*from)
if (to->addr_len != from->addr_len)
return;
+ /* See the above comments inside dev_uc_unsync(). */
netif_addr_lock_bh(from);
netif_addr_lock_nested(to);
__hw_addr_unsync(&to->mc, &from->mc, to->addr_len);
--
2.27.0
