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From: Hangbin Liu <liuhangbin@gmail.com>
To: netdev@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>,
	Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
	David Ahern <dsahern@kernel.org>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Liu Jian <liujian56@huawei.com>, Taehee Yoo <ap420073@gmail.com>,
	Jiri Benc <jbenc@redhat.com>
Subject: [IGMP Discuss] Should we use one lock for struct ip_mc_list ?
Date: Thu, 8 Sep 2022 11:40:21 +0800	[thread overview]
Message-ID: <YxlkJc+QHfDAc95s@Laptop-X1> (raw)

Hi,

When reviewing commit 23d2b94043ca ("igmp: Add ip_mc_list lock in
ip_check_mc_rcu"). Jiri pointed that struct ip_mc_list is protected by
different lock.

In function ip_check_mc_rcu() and ip_mc_del_src(), the struct ip_mc_list
in in_dev->mc_list is protected by the lock of struct ip_mc_list itself.

But in function igmpv3_send_cr, the ip_mc_list in in_dev->mc_tomb is
protected by in_dev->mc_tomb_lock.

This is no clear doc about what is protected by ip_mc_list->lock.

Is it OK for a single field that be protected by different locks?

Taehee did an update for MLD by using one mc_lock in commit 63ed8de4be81
("mld: add mc_lock for protecting per-interface mld data"). Should we also
do this on IGMP?

Thanks
Hangbin

                 reply	other threads:[~2022-09-08  3:40 UTC|newest]

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