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 <47bb83d0111f1132bbf532c16be483c5efbe839f.camel@mellanox.com>
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From:   Chuhong Yuan <hslester96@gmail.com>
Date:   Sat, 3 Aug 2019 10:42:31 +0800
Message-ID: <CANhBUQ1wZPinWicu2c_VZjpTtP_9+AxB=7zn+ymPyYVo_rsxZQ@mail.gmail.com>
Subject: Re: [PATCH] net/mlx4_core: Use refcount_t for refcount
To:     Saeed Mahameed <saeedm@mellanox.com>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "davem@davemloft.net" <davem@davemloft.net>,
        Tariq Toukan <tariqt@mellanox.com>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>
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Saeed Mahameed <saeedm@mellanox.com> =E4=BA=8E2019=E5=B9=B48=E6=9C=883=E6=
=97=A5=E5=91=A8=E5=85=AD =E4=B8=8A=E5=8D=882:38=E5=86=99=E9=81=93=EF=BC=9A
>
> On Sat, 2019-08-03 at 00:10 +0800, Chuhong Yuan wrote:
> > Chuhong Yuan <hslester96@gmail.com> =E4=BA=8E2019=E5=B9=B48=E6=9C=882=
=E6=97=A5=E5=91=A8=E4=BA=94 =E4=B8=8B=E5=8D=888:10=E5=86=99=E9=81=93=EF=BC=
=9A
> > > refcount_t is better for reference counters since its
> > > implementation can prevent overflows.
> > > So convert atomic_t ref counters to refcount_t.
> > >
> > > Also convert refcount from 0-based to 1-based.
> > >
> >
> > It seems that directly converting refcount from 0-based
> > to 1-based is infeasible.
> > I am sorry for this mistake.
>
> Just curious, why not keep it 0 based and use refcout_t ?
>
> refcount API should have the same semantics as atomic_t API .. no ?

refcount API will warn when increase a 0 refcount.
It regards this as a use-after-free.