Re: [Xen-devel] [PATCH v3 6/7] libxl: Fix libxl_set_memory_target return value

[George Dunlap <George.Dunlap@xxxxxxxxxxxxx>]

On Mon, May 9, 2016 at 9:21 AM, Paulina Szubarczyk
<paulinaszubarczyk@xxxxxxxxx> wrote:
> On Wed, 2016-04-27 at 15:29 +0100, Wei Liu wrote:
>> On Wed, Apr 20, 2016 at 10:04:03AM +0200, Paulina Szubarczyk wrote:
>> > libxl_set_memory_target seems to have the following return values:
>> >
>> > * 1 on failure, if the failure happens because of a xenstore error *or*
>> > * invalid target
>> >
>> > * -1 if the setmaxmem hypercall
>>
>> If the setmaxmem hypercall fails?
> The setmaxmem hypercall returns -1 and sets errno on error and in fact
> is the same behavior for set_pod_target. I am going to corrected the log
> to:
> "
>  '1' : on failure, if the failure happens because of a xenstore error
>        *or* invalid target
>  '-1': on error, the setmaxmem and set_pod_target hypercalls
>        return -1 and set errno appropriately.
> "
>>
>> >
>> > * -errno if the set_pod_target hypercall target fails
>> >
>> > * 0 on success
>> >
>> > Make it consistently return ERROR_FAIL on failure, unless the
>> > parameters were invalid, in which case return ERROR_INVAL.
>> >
>>
>> All in all the error code handling is not very sane in this function, so
>> I'm fine with fixing it with something better.
>>
>> > In accordance with CODING_SYTLE:
>> >
>> > 1. Leave rc uninitialized, and set when an error is detected
>> >
>> > 2. Use 'r' for return values to functions whose return values are a
>> > different error space (like xc_domain_setmaxmem and
>> > xc_domain_set_pod_target)
>> >
>> > 3. Use 'lrc' for return values to local functions libxl__*
>> > where a failure means retry, rather than fail the whole function
>> > (libxl__fill_dom0_memory_info), to reduce the risk of that.
>> >
>> > Signed-off-by: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
>> > Signed-off-by: Paulina Szubarczyk <paulinaszubarczyk@xxxxxxxxx>
>>
>> The code looks good to me.
> Could you help me understand if the comments like "looks good to me"
> should be marked in any way in resending packets?

No, it's just informational to you the sender.  It generally means, "I
would have given an Acked-by (or a Reviewed-by) if it weren't for the
other issues that I've raised."

Without that, as a submitter, you're a bit in the dark -- in this
case, you know that the reviewer has found some faults in the
changelog; but you don't know if they've even looked at the code, and
might find some other faults after you re-send it.

 -George

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