linux-kernel - Re: [PATCH v6 09/18] xen/pvcalls: implement bind command

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Message-ID: <alpine.DEB.2.10.1707051417440.2919@sstabellini-ThinkPad-X260>
Date:   Wed, 5 Jul 2017 14:18:21 -0700 (PDT)
From:   Stefano Stabellini <sstabellini@...nel.org>
To:     Juergen Gross <jgross@...e.com>
cc:     Stefano Stabellini <sstabellini@...nel.org>,
        xen-devel@...ts.xen.org, linux-kernel@...r.kernel.org,
        boris.ostrovsky@...cle.com,
        Stefano Stabellini <stefano@...reto.com>
Subject: Re: [PATCH v6 09/18] xen/pvcalls: implement bind command

On Tue, 4 Jul 2017, Juergen Gross wrote:
> On 03/07/17 23:08, Stefano Stabellini wrote:
> > Allocate a socket. Track the allocated passive sockets with a new data
> > structure named sockpass_mapping. It contains an unbound workqueue to
> > schedule delayed work for the accept and poll commands. It also has a
> > reqcopy field to be used to store a copy of a request for delayed work.
> > Reads/writes to it are protected by a lock (the "copy_lock" spinlock).
> > Initialize the workqueue in pvcalls_back_bind.
> > 
> > Implement the bind command with inet_bind.
> > 
> > The pass_sk_data_ready event handler will be added later.
> > 
> > Signed-off-by: Stefano Stabellini <stefano@...reto.com>
> > CC: boris.ostrovsky@...cle.com
> > CC: jgross@...e.com
> > ---
> >  drivers/xen/pvcalls-back.c | 87 ++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 87 insertions(+)
> > 
> > diff --git a/drivers/xen/pvcalls-back.c b/drivers/xen/pvcalls-back.c
> > index 1bc2620..dae91fb 100644
> > --- a/drivers/xen/pvcalls-back.c
> > +++ b/drivers/xen/pvcalls-back.c
> > @@ -78,6 +78,18 @@ struct sock_mapping {
> >  	struct pvcalls_ioworker ioworker;
> >  };
> >  
> > +struct sockpass_mapping {
> > +	struct list_head list;
> > +	struct pvcalls_fedata *fedata;
> > +	struct socket *sock;
> > +	uint64_t id;
> > +	struct xen_pvcalls_request reqcopy;
> > +	spinlock_t copy_lock;
> > +	struct workqueue_struct *wq;
> > +	struct work_struct register_work;
> > +	void (*saved_data_ready)(struct sock *sk);
> > +};
> > +
> >  static irqreturn_t pvcalls_back_conn_event(int irq, void *sock_map);
> >  static int pvcalls_back_release_active(struct xenbus_device *dev,
> >  				       struct pvcalls_fedata *fedata,
> > @@ -263,9 +275,84 @@ static int pvcalls_back_release(struct xenbus_device *dev,
> >  	return 0;
> >  }
> >  
> > +static void __pvcalls_back_accept(struct work_struct *work)
> > +{
> > +}
> > +
> > +static void pvcalls_pass_sk_data_ready(struct sock *sock)
> > +{
> > +}
> > +
> >  static int pvcalls_back_bind(struct xenbus_device *dev,
> >  			     struct xen_pvcalls_request *req)
> >  {
> > +	struct pvcalls_fedata *fedata;
> > +	int ret, err;
> > +	struct socket *sock;
> 
> Get rid of sock, ...

OK


> > +	struct sockpass_mapping *map;
> > +	struct xen_pvcalls_response *rsp;
> > +
> > +	fedata = dev_get_drvdata(&dev->dev);
> > +
> > +	map = kzalloc(sizeof(*map), GFP_KERNEL);
> > +	if (map == NULL) {
> > +		ret = -ENOMEM;
> > +		goto out;
> > +	}
> > +
> > +	INIT_WORK(&map->register_work, __pvcalls_back_accept);
> > +	spin_lock_init(&map->copy_lock);
> > +	map->wq = alloc_workqueue("pvcalls_wq", WQ_UNBOUND, 1);
> > +	if (!map->wq) {
> > +		ret = -ENOMEM;
> > +		kfree(map);
> 
> Move kfree(map) to the exit path, ...

OK


> > +		goto out;
> > +	}
> > +
> > +	ret = sock_create(AF_INET, SOCK_STREAM, 0, &sock);
> 
> use &map->sock here, ...

OK


> > +	if (ret < 0) {
> > +		destroy_workqueue(map->wq);
> 
> move destory_workqueue() to the exit path, ...

OK


> > +		kfree(map);
> > +		goto out;
> > +	}
> > +
> > +	ret = inet_bind(sock, (struct sockaddr *)&req->u.bind.addr,
> > +			req->u.bind.len);
> > +	if (ret < 0) {
> > +		sock_release(sock);
> 
> and sock_release, too, ...

OK


> > +		destroy_workqueue(map->wq);
> > +		kfree(map);
> > +		goto out;
> > +	}
> > +
> > +	map->fedata = fedata;
> > +	map->sock = sock;
> > +	map->id = req->u.bind.id;
> > +
> > +	down(&fedata->socket_lock);
> > +	err = radix_tree_insert(&fedata->socketpass_mappings, map->id,
> > +				map);
> 
> User ret instead of err?

OK


> > +	up(&fedata->socket_lock);
> > +	if (err) {
> > +		ret = err;
> > +		sock_release(sock);
> > +		destroy_workqueue(map->wq);
> > +		kfree(map);
> > +		goto out;
> > +	}
> > +
> > +	write_lock_bh(&sock->sk->sk_callback_lock);
> > +	map->saved_data_ready = sock->sk->sk_data_ready;
> > +	sock->sk->sk_user_data = map;
> > +	sock->sk->sk_data_ready = pvcalls_pass_sk_data_ready;
> > +	write_unlock_bh(&sock->sk->sk_callback_lock);
> > +
> > +out:
> > +	rsp = RING_GET_RESPONSE(&fedata->ring, fedata->ring.rsp_prod_pvt++);
> > +	rsp->req_id = req->req_id;
> > +	rsp->cmd = req->cmd;
> > +	rsp->u.bind.id = req->u.bind.id;
> > +	rsp->ret = ret;
> 
> ... have a common error exit handling:
> +	if (ret) {
> +		if (map && map->sock)
> +			sock_release(map->sock);
> +		if (map && map->wq)
> +			destroy_workqueue(map->wq);
> +		kfree(map);
> +	}
 
All good suggestions, I'll make all changes.