Re: [lustre-devel] [PATCH 05/12] staging: lustre: Optimize error handling in class_register_type()

Oleg Drokin
2016-07-26T19:16:03Z

On Jul 26, 2016, at 3:11 PM, Oleg Drokin wrote:

>
> On Jul 26, 2016, at 3:05 PM, SF Markus Elfring wrote:
>
>> From: Markus Elfring <elfring@users.sourceforge.net>
>> Date: Tue, 26 Jul 2016 14:23:23 +0200
>>
>> Return a constant error code without storing it in the local variable "rc"
>> after a failed memory allocation at the beginning of this function.
>>
>> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
>> ---
>> drivers/staging/lustre/lustre/obdclass/genops.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/drivers/staging/lustre/lustre/obdclass/genops.c b/drivers/staging/lustre/lustre/obdclass/genops.c
>> index fd5e61f..4752091 100644
>> --- a/drivers/staging/lustre/lustre/obdclass/genops.c
>> +++ b/drivers/staging/lustre/lustre/obdclass/genops.c
>> @@ -152,10 +152,9 @@ int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
>> return -EEXIST;
>> }
>>
>> - rc = -ENOMEM;
>
> NAK.
> when you do this, the next statement below breaks:

Ah, I see there was patch 4 before patch 5 that actually placed rc assignments
everywhere.

So I guess it is fine after all.

Sorry for the noise.

>
>> type = kzalloc(sizeof(*type), GFP_NOFS);
>> if (!type)
>> - return rc;
>> + return -ENOMEM;
>>
>> type->typ_dt_ops = kzalloc(sizeof(*type->typ_dt_ops), GFP_NOFS);
>> if (!type->typ_dt_ops) {
> …
> goto failed;
>
> failed:
> …
> return rc;
>
> So we are now returning an unitialized rc, did you get a gcc warning about it when compiling?
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