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Message-Id: <20190819.173227.816238311420289865.davem@davemloft.net>
To:     liuhangbin@gmail.com
Cc:     netdev@vger.kernel.org, challa@noironetworks.com,
        dsahern@gmail.com, jishi@redhat.com
Subject: Re: [PATCH net] ipv6/addrconf: allow adding multicast addr if
 IFA_F_MCAUTOJOIN is set
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20190813135232.27146-1-liuhangbin@gmail.com>
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From: Hangbin Liu <liuhangbin@gmail.com>
Date: Tue, 13 Aug 2019 21:52:32 +0800

> The ip address autojoin is not working for IPv6 as ipv6_add_addr()
> will return -EADDRNOTAVAIL when adding a multicast address.
> 
> Reported-by: Jianlin Shi <jishi@redhat.com>
> Fixes: 93a714d6b53d ("multicast: Extend ip address command to enable multicast group join/leave on")
> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>

I don't understand how all of this works and why ipv6_add_addr(), which
seems designed explicitly to exclude multicast addresses, should accept
them and what all of the possible fallout might be from such a change.

Your commit message is way too terse and makes it impossible to evaluate
your change.  Really, a change of this nature should have a couple paragraphs
of text explaining the existing situation, what is wrong with it, how you
are fixing it, and why you are fixing it that way.

Thanks.