netdev - Re: [PATCH 2/2] cnic: Use refcount

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Message-ID: <CACKFLi=r11QYhMbO56EDY4mNOB_x3jkR-_zWh8hg_-GL-=t0rg@mail.gmail.com>
Date:   Thu, 1 Aug 2019 16:15:47 -0700
From:   Michael Chan <michael.chan@...adcom.com>
To:     Chuhong Yuan <hslester96@...il.com>
Cc:     "David S . Miller" <davem@...emloft.net>,
        Netdev <netdev@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] cnic: Use refcount_t for refcount

On Wed, Jul 31, 2019 at 7:22 PM Chuhong Yuan <hslester96@...il.com> wrote:
>
> Michael Chan <michael.chan@...adcom.com> 于2019年8月1日周四 上午1:58写道：
> >
> > On Wed, Jul 31, 2019 at 5:22 AM Chuhong Yuan <hslester96@...il.com> wrote:
> >
> > >  static void cnic_ctx_wr(struct cnic_dev *dev, u32 cid_addr, u32 off, u32 val)
> > > @@ -494,7 +494,7 @@ int cnic_register_driver(int ulp_type, struct cnic_ulp_ops *ulp_ops)
> > >         }
> > >         read_unlock(&cnic_dev_lock);
> > >
> > > -       atomic_set(&ulp_ops->ref_count, 0);
> > > +       refcount_set(&ulp_ops->ref_count, 0);
> > >         rcu_assign_pointer(cnic_ulp_tbl[ulp_type], ulp_ops);
> > >         mutex_unlock(&cnic_lock);
> > >
> >
> > Willem's comment applies here too.  The driver needs to be modified to
> > count from 1 to use refcount_t.
> >
> > Thanks.
>
> I have revised this problem but find the other two refcounts -
> cnic_dev::ref_count
> and cnic_sock::ref_count have no set.
> I am not sure where to initialize them to 1.
>
> Besides, should ulp_ops->ref_count be set to 0 when unregistered?

I will send a patch to fix up the initialization of all the atomic ref
counts.  After that, you can add your patch to convert to refcount_t.