Re: [PATCH] s390/dasd: fix double module refcount decrement

["Jan Höppner" <hoeppner@linux.ibm.com>]

On 10/01/2024 17:01, Miroslav Franc wrote:
> Once the discipline is associated with the device, deleting the device
> takes care of decrementing the module's refcount.  Doing it manually on
> this error path causes refcount to artificially decrease on each error
> while it should just stay the same.
> 
> Fixes: c020d722b110 ("s390/dasd: fix panic during offline processing")
> Signed-off-by: Miroslav Franc <mfranc@suse.cz>
> ---
>  drivers/s390/block/dasd.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
> index 833cfab7d877..739da1c2b71f 100644
> --- a/drivers/s390/block/dasd.c
> +++ b/drivers/s390/block/dasd.c
> @@ -3546,8 +3546,6 @@ int dasd_generic_set_online(struct ccw_device *cdev,
>  	if (rc) {
>  		pr_warn("%s Setting the DASD online with discipline %s failed with rc=%i\n",
>  			dev_name(&cdev->dev), discipline->name, rc);
> -		module_put(discipline->owner);
> -		module_put(base_discipline->owner);

Good catch. I think there is one more line above this part that should
also be removed:

if (!try_module_get(discipline->owner)) {
        module_put(base_discipline->owner); <---
        dasd_delete_device(device);
        return -EINVAL;
}

Can you add it to the patch? Thanks!

>  		dasd_delete_device(device);
>  		return rc;
>  	}
>