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

[Wei Yang <richardw.yang@linux.intel.com>]

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.

>Thanks,
>Star
>
>> 
>> >
>> >Thanks,
>> >Star
>> >
>> >>      }
>> >>  out:
>> >>      g_slist_free(list);
>> >> --
>> >> 2.17.1
>> >>
>> 
>> --
>> Wei Yang
>> Help you, Help me

-- 
Wei Yang
Help you, Help me