[PATCH 02/02] force module loaded with partitions set

[Yang Rui Rui]

On 03/14/2011 04:53 PM, Artem Bityutskiy wrote:
> On Mon, 2011-03-14 at 16:57 +0800, Yang Rui Rui wrote:
>> On 03/14/2011 04:43 PM, Artem Bityutskiy wrote:
>>> On Mon, 2011-03-14 at 09:51 +0800, Yang Ruirui wrote:
>>>> From: Yang Ruirui<ruirui.r.yang at tieto.com>
>>>>
>>>> partitions can not be set after module loaded, the moduel param
>> mode is 0444.
>>>>
>>>> this patch force module loaded with param partitions set, if user
>> does not
>>>> set partitions then give out a warning and return -EINVAL
>>>>
>>>> Signed-off-by: Yang Ruirui<ruirui.r.yang at tieto.com>
>>>> Tested-by: Shao Yanqing<yanqing.shao at tieto.com>
>>>> Tested-by: Xiao Yang<yang.xiao at tieto.com>
>>>> ---
>>>>    drivers/mtd/mtdswap.c |    6 ++++++
>>>>    1 file changed, 6 insertions(+)
>>>>
>>>> --- mtd-2.6-fc2ff59.orig/drivers/mtd/mtdswap.c	2011-03-14
>> 09:36:09.283329099 +0800
>>>> +++ mtd-2.6-fc2ff59/drivers/mtd/mtdswap.c	2011-03-14
>> 09:46:30.229993534 +0800
>>>> @@ -1569,6 +1569,12 @@ static struct mtd_blktrans_ops mtdswap_o
>>>>
>>>>    static int __init mtdswap_modinit(void)
>>>>    {
>>>> +	if (!partitions[0]) {
>>>> +		printk(KERN_WARNING
>>>> +			"Please load mtdswap with correct partitions param\n");
>>>> +		return -EINVAL;
>>>> +	}
>>>
>>> I think a similar check is done in mtdswap_add_mtd() ?
>>>
>>>
>>
>> Yes, that one should be removed if this is ok. This module just waste
>> memory without partitions set. And there's no chance to pass in the
>> params.
>
> I agree that the problem you are solving exist. But I think I do not
> agree with the solution. There are many other ways to end up with
> mtdswap module loaded but not functioning, e.g., users passes incorrect
> module parameters. Basically, any failed check in 'mtdswap_add_mtd()'.
>
> IOW, you are solving just one of many similar issues.

Right, agree.

>
> I think you should rather re-work the framework a bit and make the
> "->add_mtd()" call-back return an integer error code. Then we could just
> return errors on error and prevent the module from being loaded.
>

I'm thinking is it possible to pass partitions param later? ie. use sysfs attribute?

Anyway, I will check the code again to see if can change as your suggestion.

-- 
Thanks
Yang Ruirui