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

Oleg Drokin
2016-07-26T19:11:48Z

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:

> 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?