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Date:   Mon, 09 Aug 2021 06:12:55 +0000
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From:   yajun.deng@linux.dev
Message-ID: <489e6f1ce9f8de6fd8765d82e1e47827@linux.dev>
Subject: Re: [PATCH net-next] net: sock: add the case if sk is NULL
To:     "Jakub Kicinski" <kuba@kernel.org>
Cc:     davem@davemloft.net, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
In-Reply-To: <20210806061136.54e6926e@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
References: <20210806061136.54e6926e@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
 <20210806063815.21541-1-yajun.deng@linux.dev>
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August 6, 2021 9:11 PM, "Jakub Kicinski" <kuba@kernel.org> wrote:=0A=0A> =
On Fri, 6 Aug 2021 14:38:15 +0800 Yajun Deng wrote:=0A> =0A>> Add the cas=
e if sk is NULL in sock_{put, hold},=0A>> The caller is free to use it.=
=0A>> =0A>> Signed-off-by: Yajun Deng <yajun.deng@linux.dev>=0A> =0A> The=
 obvious complaint about this patch (and your previous netdev patch)=0A> =
is that you're spraying branches everywhere in the code. Sure, it may=0A=
=0ASorry for that, I'll be more normative in later submission.=0A> be oka=
y for free(), given how expensive of an operation that is but=0A> is havi=
ng refcounting functions accept NULL really the best practice?=0A> =0A> C=
an you give us examples in the kernel where that's the case?=0A=0A0   inc=
lude/net/neighbour.h         neigh_clone()=0A1   include/linux/cgroup.h  =
        get_cgroup_ns() and put_cgroup_ns()  (This is very similar to my =
submission)=0A2   include/linux/ipc_namespace.h   get_ipc_ns()=0A3   incl=
ude/linux/posix_acl.h       posix_acl_dup()=0A4   include/linux/pid.h    =
         get_pid()=0A5   include/linux/user_namespace.h  get_user_ns()