netdev - Re: [RFC next-next v2 1/5] net: marvell: prestera: Add driver for Prestera family ASIC devices

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Message-ID: <20200512145352.GC31516@plvision.eu>
Date:   Tue, 12 May 2020 17:53:52 +0300
From:   Vadym Kochan <vadym.kochan@...ision.eu>
To:     Jiri Pirko <jiri@...nulli.us>
Cc:     netdev@...r.kernel.org, "David S. Miller" <davem@...emloft.net>,
        Oleksandr Mazur <oleksandr.mazur@...ision.eu>,
        Serhiy Boiko <serhiy.boiko@...ision.eu>,
        Serhiy Pshyk <serhiy.pshyk@...ision.eu>,
        Volodymyr Mytnyk <volodymyr.mytnyk@...ision.eu>,
        Taras Chornyi <taras.chornyi@...ision.eu>,
        Andrii Savka <andrii.savka@...ision.eu>,
        Jiri Pirko <jiri@...lanox.com>,
        Ido Schimmel <idosch@...lanox.com>,
        Andrew Lunn <andrew@...n.ch>,
        Chris Packham <Chris.Packham@...iedtelesis.co.nz>
Subject: Re: [RFC next-next v2 1/5] net: marvell: prestera: Add driver for
 Prestera family ASIC devices

On Mon, May 11, 2020 at 12:32:22PM +0200, Jiri Pirko wrote:

[...]

> 
> This is RCU list. Treat it accordingly.
> 
> 
> >+	spin_unlock(&sw->ports_lock);
> 
> I don't follow, why do you need to protect the list by spinlock here?
> More to that, why do you need the port_list reader-writer
> protected (by rcu)? Is is possible that you add/remove port in the same
> time packets are flying in?
> 
> If yes, you need to ensure the structs are in the memory (free_rcu,
> synchronize_rcu). But I believe that you should disable that from
> happening in HW.
> 
> 
> >+

[...]

> >+
> >+static int prestera_switch_init(struct prestera_switch *sw)
> >+{
> >+	int err;
> >+
> >+	err = prestera_hw_switch_init(sw);
> >+	if (err) {
> >+		dev_err(prestera_dev(sw), "Failed to init Switch device\n");
> >+		return err;
> >+	}
> >+
> >+	memcpy(sw->base_mac, base_mac_addr, sizeof(sw->base_mac));
> >+	spin_lock_init(&sw->ports_lock);
> >+	INIT_LIST_HEAD(&sw->port_list);
> >+
> >+	err = prestera_hw_switch_mac_set(sw, sw->base_mac);
> >+	if (err)
> >+		return err;
> >+
> >+	err = prestera_rxtx_switch_init(sw);
> >+	if (err)
> >+		return err;
> >+
> >+	err = prestera_event_handlers_register(sw);
> >+	if (err)
> >+		goto err_evt_handlers;
> >+
> >+	err = prestera_create_ports(sw);
> >+	if (err)
> >+		goto err_ports_create;
> >+
> >+	return 0;
> >+
> >+err_ports_create:
> 
> You are missing prestera_event_handlers_unregister(sw); call here.
> 
it is handled below in prestera_switch_fini().

> 
> >+err_evt_handlers:
> >+	prestera_rxtx_switch_fini(sw);
> >+
> >+	return err;
> >+}
> >+
> >+static void prestera_switch_fini(struct prestera_switch *sw)
> >+{
> >+	prestera_destroy_ports(sw);
> >+	prestera_event_handlers_unregister(sw);
> >+	prestera_rxtx_switch_fini(sw);
> >+}
> >+
> >+int prestera_device_register(struct prestera_device *dev)
> >+{
> >+	struct prestera_switch *sw;
> >+	int err;
> >+
> >+	sw = kzalloc(sizeof(*sw), GFP_KERNEL);
> >+	if (!sw)
> >+		return -ENOMEM;
> >+
> >+	dev->priv = sw;
> >+	sw->dev = dev;
> >+
> >+	err = prestera_switch_init(sw);
> >+	if (err) {
> >+		kfree(sw);
> >+		return err;
> >+	}
> >+
> >+	registered_switch = sw;
> >+	return 0;
> >+}
> >+EXPORT_SYMBOL(prestera_device_register);
> >+
> >+void prestera_device_unregister(struct prestera_device *dev)
> >+{
> >+	struct prestera_switch *sw = dev->priv;
> >+
> >+	registered_switch = NULL;
> >+	prestera_switch_fini(sw);
> >+	kfree(sw);
> >+}
> >+EXPORT_SYMBOL(prestera_device_unregister);
> >+
> >+static int __init prestera_module_init(void)
> >+{
> >+	if (!base_mac) {
> >+		pr_err("[base_mac] parameter must be specified\n");
> >+		return -EINVAL;
> >+	}
> >+	if (!mac_pton(base_mac, base_mac_addr)) {
> >+		pr_err("[base_mac] parameter has invalid format\n");
> >+		return -EINVAL;
> >+	}
> >+
> >+	prestera_wq = alloc_workqueue("prestera", 0, 0);
> >+	if (!prestera_wq)
> >+		return -ENOMEM;
> >+
> >+	return 0;
> >+}
> >+
> >+static void __exit prestera_module_exit(void)
> >+{
> >+	destroy_workqueue(prestera_wq);
> >+}
> >+
> >+module_init(prestera_module_init);
> >+module_exit(prestera_module_exit);
> >+
> >+MODULE_AUTHOR("Marvell Semi.");
> >+MODULE_LICENSE("Dual BSD/GPL");
> >+MODULE_DESCRIPTION("Marvell Prestera switch driver");
> >+
> >+module_param(base_mac, charp, 0);
> 
> No please.
> 
> 
> [..]
>