Re: [Qemu-devel] [PATCH v2 1/2] memory-device: not necessary to use goto for the last check

["Zeng, Star" <star.zeng@intel.com>]

> -----Original Message-----
> From: Wei Yang [mailto:richardw.yang@linux.intel.com]
> Sent: Monday, August 19, 2019 10:39 AM
> To: David Hildenbrand <david@redhat.com>
> Cc: Wei Yang <richardw.yang@linux.intel.com>; Zeng, Star
> <star.zeng@intel.com>; imammedo@redhat.com; qemu-devel@nongnu.org;
> mst@redhat.com
> Subject: Re: [Qemu-devel] [PATCH v2 1/2] memory-device: not necessary to
> use goto for the last check
> 
> On Thu, Aug 08, 2019 at 09:06:21AM +0200, David Hildenbrand wrote:
> >On 08.08.19 04:38, Wei Yang wrote:
> >> On Thu, Aug 08, 2019 at 02:30:02AM +0000, Zeng, Star wrote:
> >>>> -----Original Message-----
> >>>> From: Wei Yang [mailto:richardw.yang@linux.intel.com]
> >>>> Sent: Thursday, August 8, 2019 10:13 AM
> >>>> To: Zeng, Star <star.zeng@intel.com>
> >>>> Cc: Wei Yang <richardw.yang@linux.intel.com>;
> >>>> qemu-devel@nongnu.org; imammedo@redhat.com;
> david@redhat.com;
> >>>> mst@redhat.com
> >>>> Subject: Re: [Qemu-devel] [PATCH v2 1/2] memory-device: not
> >>>> necessary to use goto for the last check
> >>>>
> >>>> On Thu, Aug 08, 2019 at 01:42:14AM +0000, Zeng, Star wrote:
> >>>>>> -----Original Message-----
> >>>>>> From: Qemu-devel [mailto:qemu-devel-
> >>>>>> bounces+star.zeng=intel.com@nongnu.org] On Behalf Of Wei Yang
> >>>>>> Sent: Tuesday, July 30, 2019 8:38 AM
> >>>>>> To: qemu-devel@nongnu.org
> >>>>>> Cc: imammedo@redhat.com; david@redhat.com; Wei Yang
> >>>>>> <richardw.yang@linux.intel.com>; mst@redhat.com
> >>>>>> Subject: [Qemu-devel] [PATCH v2 1/2] memory-device: not
> necessary
> >>>>>> to use goto for the last check
> >>>>>>
> >>>>>> We are already at the last condition check.
> >>>>>>
> >>>>>> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
> >>>>>> Reviewed-by: Igor Mammedov <imammedo@redhat.com>
> >>>>>> Reviewed-by: David Hildenbrand <david@redhat.com>
> >>>>>> ---
> >>>>>>  hw/mem/memory-device.c | 1 -
> >>>>>>  1 file changed, 1 deletion(-)
> >>>>>>
> >>>>>> diff --git a/hw/mem/memory-device.c b/hw/mem/memory-
> device.c
> >>>> index
> >>>>>> 5f2c408036..df3261b32a 100644
> >>>>>> --- a/hw/mem/memory-device.c
> >>>>>> +++ b/hw/mem/memory-device.c
> >>>>>> @@ -186,7 +186,6 @@ static uint64_t
> >>>>>> memory_device_get_free_addr(MachineState *ms,
> >>>>>>      if (!range_contains_range(&as, &new)) {
> >>>>>>          error_setg(errp, "could not find position in guest address space
> for "
> >>>>>>                     "memory device - memory fragmented due to
> alignments");
> >>>>>> -        goto out;
> >>>>>
> >>>>> Is it better to return 0 (or set new_addr to 0) for this error
> >>>>> path and another
> >>>> remaining "goto out" path?
> >>>>>
> >>>>
> >>>> I may not get your point.
> >>>>
> >>>> We set errp which is handled in its caller. By doing so, the error is
> propagated.
> >>>>
> >>>> Do I miss something?
> >>>
> >>> Yes, you are right. Currently, the caller is checking errp, but not the
> returned address, so there should be no issue.
> >>> But when you see other error paths, you will find they all return 0.
> >>> To be aligned (return 0 when error), so just suggest also returning
> >>> 0 for these two "goto out" error path. :)
> >>>
> >>
> >> You may have some point.
> >>
> >> Let's see whether others have the same taste, or we can refine it
> separately.
> >>
> >
> >I don't think that's necessary (callers really should check for errors
> >before using the return values), but I would also not object to that change.
> >
> 
> In case there is no strong requirement to refactor the code. I would leave it
> here.

It was just my suggestion. I am fine with any preference you and other experts have.

Thanks,
Star

> 
> >--
> >
> >Thanks,
> >
> >David / dhildenb
> 
> --
> Wei Yang
> Help you, Help me