Re: [PATCH] xen/xenbus: Use 'void' instead of 'int' for the return of xenbus_switch_state()

Chen Gang
2014-09-30T07:59:03Z

On 9/29/14 22:02, Konrad Rzeszutek Wilk wrote:
> On Sat, Sep 27, 2014 at 12:36:42AM +0800, Chen Gang wrote:
>> When xenbus_switch_state() fails, it will call xenbus_switch_fatal()
>
> Only on the first depth, not on the subsequent ones (as in if
> the first xenbus_switch_fail fails, it won't try to call
> xenbus_switch_state again and again).
>

Yeah, I guess you want to give more completion for this comment, do not
mean the original comments is incorrect.

[...]
>>
>> Also need be sure that all callers which check the return value must let
>> 'err' be 0.
>
> I am bit uncomfortable with that, that is due to:
>
>
> .. snip..
>> diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
>> index 9c47b89..b5c3d47 100644
>> --- a/drivers/net/xen-netback/xenbus.c
>> +++ b/drivers/net/xen-netback/xenbus.c
>> @@ -337,10 +337,7 @@ static int netback_probe(struct xenbus_device *dev,
>> if (err)
>> pr_debug("Error writing multi-queue-max-queues\n");
>>
>> - err = xenbus_switch_state(dev, XenbusStateInitWait);
>> - if (err)
>> - goto fail;
>> -
>> + xenbus_switch_state(dev, XenbusStateInitWait);
>
> Which if it fails it won't call:
>
> 354 fail:
> 355 pr_debug("failed\n");
> 356 netback_remove(dev);
> 357 return err;
>

Originally, I intended left 'fail' code block for the next patch (which
I thought the next patch would need it).

Hmm... but any way, originally, I really need give additional comments
for it.

[...]

I skip all other contents which have already discussed by maintainers,
if I really miss something, please let me know.

Thanks.
--
Chen Gang

Open, share, and attitude like air, water, and life which God blessed