Re: [Qemu-trivial] [PATCH] block: Remove unused assignment (fixes warning from clang)

[Stefan Weil <sw@weilnetz.de>]

Am 29.09.2013 21:44, schrieb Michael Tokarev:
> 28.09.2013 13:55, Stefan Weil wrote:
[...]
>> diff --git a/blockdev.c b/blockdev.c
>> index 8aa66a9..8c83f6f 100644
>> --- a/blockdev.c
>> +++ b/blockdev.c
>> @@ -1926,7 +1926,6 @@ void qmp_drive_mirror(const char *device, const
>> char *target,
>>       } else {
>>           switch (mode) {
>>           case NEW_IMAGE_MODE_EXISTING:
>> -            ret = 0;
>>               break;
>
> While this one is obviously unused assignment,
> there's on more usage of `ret' variable in this
> function, -- it is to store the return value
> from bdrv_open():
>
>     ret = bdrv_open(target_bs, target, NULL, flags |
> BDRV_O_NO_BACKING, drv,
>                     &local_err);
>     if (ret < 0) {...
>
> What's the rule about converting that into if() ?
>
> Thanks,
>
> /mjt

Is there a rule for cases like that? This pattern is very common in QEMU
code
(several occurrences in blockdev.c). Should we eliminate the 'ret' variable?
I don't think it's worth the effort.

Stefan