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Date:   Fri, 10 May 2019 15:13:33 -0700 (PDT)
Message-Id: <20190510.151333.266788690200661708.davem@davemloft.net>
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Subject: Re: [PATCH v2 2/3] netns: add netns_evict into netns_operations
From:   David Miller <davem@davemloft.net>
In-Reply-To: <1557470163-30071-3-git-send-email-wenbinzeng@tencent.com>
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        <1557470163-30071-1-git-send-email-wenbinzeng@tencent.com>
        <1557470163-30071-3-git-send-email-wenbinzeng@tencent.com>
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From: Wenbin Zeng <wenbin.zeng@gmail.com>
Date: Fri, 10 May 2019 14:36:02 +0800

> The newly added netns_evict() shall be called when the netns inode being
> evicted. It provides another path to release netns refcounts, previously
> netns_put() is the only choice, but it is not able to release all netns
> refcount, for example, a rpc client holds two netns refcounts, these
> refcounts are supposed to be released when the rpc client is freed, but
> the code to free rpc client is normally triggered by put() callback only
> when netns refcount gets to 0, specifically:
>     refcount=0 -> cleanup_net() -> ops_exit_list -> free rpc client
> But netns refcount will never get to 0 before rpc client gets freed, to
> break the deadlock, the code to free rpc client can be put into the newly
> added netns_evict.
> 
> Signed-off-by: Wenbin Zeng <wenbinzeng@tencent.com>

Acked-by: David S. Miller <davem@davemloft.net>