Re: [PATCH 7/9] btrfs-progs: Fix Wmaybe-uninitialized warning

[Nikolay Borisov]

On 4.12.18 г. 14:22 ч., Adam Borowski wrote:
> On Tue, Dec 04, 2018 at 01:17:04PM +0100, David Sterba wrote:
>> On Fri, Nov 16, 2018 at 03:54:24PM +0800, Qu Wenruo wrote:
>>> The only location is the following code:
>>>
>>>     int level = path->lowest_level + 1;
>>>     BUG_ON(path->lowest_level + 1 >= BTRFS_MAX_LEVEL);
>>>     while(level < BTRFS_MAX_LEVEL) {
>>>             slot = path->slots[level] + 1;
>>>             ...
>>>     }
>>>     path->slots[level] = slot;
>>>
>>> Again, it's the stupid compiler needs some hint for the fact that
>>> we will always enter the while loop for at least once, thus @slot should
>>> always be initialized.
>>
>> Harsh words for the compiler, and I say not deserved. The same code
>> pasted to kernel a built with the same version does not report the
>> warning, so it's apparently a missing annotation of BUG_ON in
>> btrfs-progs that does not give the right hint.
> 
> It's be nice if the C language provided a kind of a while loop that executes
> at least once...

But it does, it's called:

do {

} while()

>