From mboxrd@z Thu Jan  1 00:00:00 1970
From: Lan Tianyu <tianyu.lan@intel.com>
Date: Wed, 12 Sep 2012 14:41:32 +0000
Subject: Re: [balbi-usb:merge-result-for-greg 66/99] drivers/usb/core/hub.c:2654 usb_get_hub_port_power_state
Message-Id: <50509F1C.2030208@intel.com>
List-Id: <kernel-janitors.vger.kernel.org>
References: <20120912082622.GB27847@localhost>
In-Reply-To: <20120912082622.GB27847@localhost>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: kernel-janitors@vger.kernel.org

On 2012/9/12 21:11, Alan Stern wrote:
> On Wed, 12 Sep 2012, Fengguang Wu wrote:
>
>> Hi Felipe,
>>
>> FYI, there are new smatch warnings show up in
>>
>> tree:   git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb.git merge-result-for-greg
>> head:   23953bde3e4d6aa8780dc054f6ad9882ac63f4f4
>> commit: e918fa161f510136fce45a524e934fe20e62c8b1 [66/99] Merge tag 'gadget-for-v3.7' into merge-result-for-greg
>>
>> drivers/usb/core/hub.c:2654 usb_get_hub_port_power_state() error: doing dma on the stack ((null))
>> drivers/usb/core/hub.c:4733 store_port_power_control() info: why not propagate 'ret' from set_port_feature() instead of -5?
>> drivers/usb/core/hub.c:4744 store_port_power_control() info: why not propagate 'ret' from clear_port_feature() instead of -5?
>>
>> vim +2654 drivers/usb/core/hub.c
>>    2644		return ret;
>>    2645	}
>>    2646	
>>    2647	static int usb_get_hub_port_power_state(struct usb_device *hdev, int port1)
>>    2648	{
>>    2649		struct usb_hub *hub = hdev_to_hub(hdev);
>>    2650		struct usb_port_status data;
>>    2651		u16 portstatus;
>>    2652		int ret;
>>    2653	
>>> 2654		ret = get_port_status(hub->hdev, port1, &data);
>>    2655		if (ret < 4) {
>>    2656			dev_err(hub->intfdev,
>>    2657				"%s failed (err = %d)\n", __func__, ret);
>>    2658			if (ret >= 0)
>>    2659				ret = -EIO;
>>    2660			return ret;
>>    2661		} else
>>    2662			portstatus = le16_to_cpu(data.wPortStatus);
>>    2663		return port_is_power_on(hub, portstatus);
>>    2664	}
>
> This is a real problem.  It looks like it really is necessary to call
> hub_port_status() here, not get_port_status().  Would you like to fix
> this?
>
Yeah. I'd like to fix it.
> The reason for changing the return codes from clear_port_feature() and
> set_port_feature() is simple.  The values they return are meant for
> internal use within the kernel, whereas the return code from
> store_port_power_control() will be passed back to userspace.
>
> Alan Stern
>


-- 
Best Regards
Tianyu Lan
linux kernel enabling team