Re: [Qemu-devel] [PATCH 2/4] block-commit: speed is an optional parameter

[Max Reitz <mreitz@redhat.com>]

On 07.04.2014 20:55, Eric Blake wrote:
> On 04/07/2014 11:29 AM, Max Reitz wrote:
>> As speed is an optional parameter for the QMP block-commit command, it
>> should be set to 0 if not given (as it is undefined if has_speed is
>> false), that is, the speed should not be limited.
>>
>> Signed-off-by: Max Reitz <mreitz@redhat.com>
>> ---
>>   blockdev.c | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/blockdev.c b/blockdev.c
>> index 0be4601..337c11f 100644
>> --- a/blockdev.c
>> +++ b/blockdev.c
>> @@ -1876,6 +1876,7 @@ void qmp_block_commit(const char *device,
>>        */
>>       BlockdevOnError on_error = BLOCKDEV_ON_ERROR_REPORT;
>>   
>> +    speed       = speed           ? speed       : 0;
> Oops, branching based on the contents of an undefined variable.  You
> meant has_speed in the second of the three uses.

Right – this way, it makes little sense but as a test for compiler 
optimizations. ;-)

Max