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From: "Guo-Fu Tseng" <cooldavid@cooldavid.org>
To: Laurent Chavey <chavey@google.com>
Cc: David Miller <davem@davemloft.net>,
	Ethan Hsiao <ethanhsiao@jmicron.com>,
	linux-netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH v2.6.33 2/2] jme: Adding lock to protect vlgrp structure.
Date: Tue, 16 Mar 2010 03:13:33 +0800	[thread overview]
Message-ID: <20100315191339.M2560@cooldavid.org> (raw)
In-Reply-To: <97949e3e1003151122q68ce19f4ja7f53ad380d3033f@mail.gmail.com>

Hi Laurent:

The vlan_rx_register is called through ioctl.
And the packet feeding is called in the tasklet.
I see no lock in register_vlan_dev(), register_vlan_device(), and vlan_ioctl_handler()
which is related to the vlan_hwaccel_receive_skb(), vlan_hwaccel_rx().

It prevents the vlgrp pointer be modified while trying to feed the packet.
Ex:
> if (jme->vlgrp) {
True.
vlan_rx_register called, vlgrp set to NULL.
>         jme->jme_vlan_rx(skb, jme->vlgrp,
>                          le16_to_cpu(rxdesc->descwb.vlan));
passing vlgrp with the value "NULL" to jme_vlan_rx.
Or it might even be modified during the vlan_hwaccel_{receive_skb|rx} call.

Please correct me if I'm wrong.

On Mon, 15 Mar 2010 11:22:48 -0700, Laurent Chavey wrote
> what does the spinlock protect ?
> 

--
Guo-Fu Tseng


  reply	other threads:[~2010-03-15 19:13 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-15  5:15 [PATCH v2.6.33 1/2] jme: Fix VLAN memory leak cooldavid
2010-03-15  5:15 ` [PATCH v2.6.33 2/2] jme: Adding lock to protect vlgrp structure cooldavid
2010-03-15 18:22   ` Laurent Chavey
2010-03-15 19:13     ` Guo-Fu Tseng [this message]
2010-03-15 22:53       ` David Miller
2010-03-16  7:15         ` Guo-Fu Tseng
2010-03-16  7:40           ` Eric Dumazet

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