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| author | Cong Wang <xiyou.wangcong@gmail.com> | 2020-06-26 11:25:27 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-06-28 21:38:27 -0700 |
| commit | e8280338c778a3f81477624267c9fa47f931477b (patch) | |
| tree | fb0513375932e0e02b72c82ff61219f6b2300ba0 /net/core | |
| parent | be74294ffa24f5fbc0d6643842e3e095447e17a2 (diff) | |
| download | linux-e8280338c778a3f81477624267c9fa47f931477b.tar.gz linux-e8280338c778a3f81477624267c9fa47f931477b.tar.bz2 linux-e8280338c778a3f81477624267c9fa47f931477b.zip | |
net: explain the lockdep annotations for dev_uc_unsync()
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 <ap420073@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/dev_addr_lists.c | 10 |
1 files changed, 10 insertions, 0 deletions
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); |