On 9/29/14 16:41, Jan Beulich wrote:
>>>> On 29.09.14 at 06:32, <jgr...@suse.com> wrote:
>> On 09/26/2014 06:38 PM, Chen Gang wrote:
>>> When failure occurs, after xenbus_dev_error(), need go to fail to let
>>> upper caller know about it.
>>>
>>> Signed-off-by: Chen Gang <gang.chen.5...@gmail.com>
>>> ---
>>> drivers/xen/xen-scsiback.c | 4 +++-
>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/xen/xen-scsiback.c b/drivers/xen/xen-scsiback.c
>>> index 847bc9c..3e430e1 100644
>>> --- a/drivers/xen/xen-scsiback.c
>>> +++ b/drivers/xen/xen-scsiback.c
>>> @@ -1222,8 +1222,10 @@ static int scsiback_probe(struct xenbus_device *dev,
>>>
>>> err = xenbus_printf(XBT_NIL, dev->nodename, "feature-sg-grant", "%u",
>>> SG_ALL);
>>> - if (err)
>>> + if (err) {
>>> xenbus_dev_error(dev, err, "writing feature-sg-grant");
>>> + goto fail;
>>> + }
>>>
>>> xenbus_switch_state(dev, XenbusStateInitWait);
>>> return 0;
>>>
>>
>> Hmm, not testing for failure was on purpose. Advertising this feature
>> is just for tuning purposes, not mandatory.
>>
>> OTOH it would really be a strange error if this xenbus_printf() fails
>> but all other operations are working, and signaling an error at the
>> time when it first shows up is a good thing. So:
>
> I disagree - failure to announce optional features should not lead to
> general failure. And this should be consistent across drivers; for
> existing examples see xen_blkbk_flush_diskcache() and
> xen_blkbk_discard().
>
During scsiback_probe(), can we sure that "feature-sg-grant" is optional
feature? For me, only according to its name, I guess not: it is about
security which is always necessary in kernel (although SG_ALL).
Thanks
--
Chen Gang
Open, share, and attitude like air, water, and life which God blessed
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
