Re: [PATCH] s390: correct misuses of module_put in appldata_generic_handler.

Zhouyi Zhou
2014-03-18T01:24:57Z

Thanks Gerald for reviewing and sorry for not elaborated it in the e-mail.

Firstly, I think you can't call module_put after fail try_module_get

Secondly, there exists duplicate module_put on the program path (the last
one is before return 0)

On Mon, Mar 17, 2014 at 9:28 PM, Gerald Schaefer
<gerald.schaefer@de.ibm.com> wrote:
> On Sat, 15 Mar 2014 21:35:40 +0800
> Zhouyi Zhou <zhouzhouyi@gmail.com> wrote:
>
>> correct misuses of module_put in appldata_generic_handler
>
> Sorry, I don't see any misuse, could you elaborate?
>
>>
>> Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
>> ---
>> arch/s390/appldata/appldata_base.c | 3 ---
>> 1 file changed, 3 deletions(-)
>>
>> diff --git a/arch/s390/appldata/appldata_base.c b/arch/s390/appldata/appldata_base.c
>> index 47c8630..683e0282 100644
>> --- a/arch/s390/appldata/appldata_base.c
>> +++ b/arch/s390/appldata/appldata_base.c
>> @@ -343,7 +343,6 @@ appldata_generic_handler(struct ctl_table *ctl, int write,
>> // protect work queue callback
>> if (!try_module_get(ops->owner)) {
>> mutex_unlock(&appldata_ops_mutex);
>> - module_put(ops->owner);
>> return -ENODEV;
>> }
>> ops->callback(ops->data); // init record
>> @@ -354,7 +353,6 @@ appldata_generic_handler(struct ctl_table *ctl, int write,
>> if (rc != 0) {
>> pr_err("Starting the data collection for %s "
>> "failed with rc=%d\n", ops->name, rc);
>> - module_put(ops->owner);
>> } else
>> ops->active = 1;
>> } else if ((buf[0] == '0') && (ops->active == 1)) {
>> @@ -365,7 +363,6 @@ appldata_generic_handler(struct ctl_table *ctl, int write,
>> if (rc != 0)
>> pr_err("Stopping the data collection for %s "
>> "failed with rc=%d\n", ops->name, rc);
>> - module_put(ops->owner);
>> }
>> mutex_unlock(&appldata_ops_mutex);
>> out:
>