linux-kernel - Re: [PATCH 2/4] staging: ozwpan: Increment port number for new device.

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Message-ID: <51FFF244.9000604@atmel.com>
Date:	Mon, 5 Aug 2013 19:43:16 +0100
From:	Rupesh Gujare <rupesh.gujare@...el.com>
To:	Dan Carpenter <dan.carpenter@...cle.com>
CC:	<devel@...uxdriverproject.org>, <gregkh@...uxfoundation.org>,
	<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/4] staging: ozwpan: Increment port number for new device.

On 05/08/13 18:53, Dan Carpenter wrote:
> On Mon, Aug 05, 2013 at 06:40:13PM +0100, Rupesh Gujare wrote:
>> This patch fixes crash issue when there is quick cycle of
>> de-enumeration & enumeration due to loss of wireless link.
>>
>> It is found that sometimes new device (or coming back device)
>> returns very fast, even before USB core read out hub status,
>> resulting in allocation of same port, which results in unstable
>> system & crash.
>>
>> Above issue is resolved by making sure that we always assign
>> new port to new device, making sure that USB core reads correct
>> hub status.
>>
> This feels like papering over the problem.  Surely the real fix
> would be to improve the reference counting.
>
> This patch is probably effective but it makes the code more subtle
> and it shows that we don't really understand what we are doing with
> regards to reference counting.
>
>

Probably this is easier way to fix issue, since we don't have reference 
count for ports & we rely on flags to check port status.
Any suggestions are appreciated.

-- 
Regards,
Rupesh Gujare

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