Re: [PATCH] tty/n_gsm.c: do not clear gsm_mux entry when the gsm is not closed

From: Peter Hurley
Date: Thu Oct 09 2014 - 15:24:12 EST

On 10/09/2014 03:13 PM, Greg Kroah-Hartman wrote:
> On Thu, Oct 09, 2014 at 03:01:46PM -0400, Peter Hurley wrote:
>> On 07/28/2014 11:13 AM, Greg Kroah-Hartman wrote:
>>> On Mon, Jul 28, 2014 at 03:16:25PM +0800, xinhui.pan wrote:
>>>>> Why can't you do dynamic reference counting of your structure, that
>>>>> would allow you to get rid of your global array, right?
>>>> Thanks for your nice comments.
>>>> Struct gsm has a ref-count already. :)
>>> Then you should be fine, no need to keep it in an array.
>>>> And also adding a ref-count is a little hard to me. :(
>>>> This global array is used to keep tracking the gsms that stands for the gsmttyXX.
>>> You shouldn't need that at all, just use a list, you don't care what the
>>> XX number is within the driver, just allocate a new one with the next
>>> available number and you should be fine.
>>>> and it can tell us if we can create a new gsm. :)
>>> You should always be able to create a new gsm if you need to :)
>>>> In gsm_init we set *gsm_tty_driver = alloc_tty_driver(256);*
>>> Why limit to 256? Just use a list, and a idr structure to allocate the
>>> minor number, and all should be good.
>> Hi Greg,
>> This is still broken in the gsm driver.
>> As much as I'd like to see someone take ownership of the gsm driver and
>> do this 'the right way', I think until that happens we should consider
>> fixing the reuse-while-in-use error.
> What happened to the gsm driver maintainers?


$ ./scripts/ -f drivers/tty/n_gsm.c
Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> (supporter:TTY LAYER)
Jiri Slaby <jslaby@xxxxxxx> (supporter:TTY LAYER)
linux-kernel@xxxxxxxxxxxxxxx (open list)

>> Would you be willing to take a patch from me that just does the bare
>> minimum to keep this from panicking in the cdev code?
> Depends on what the patch looks like :)
> Send it on, and I'll be glad to review it.


Peter Hurley
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