Messages in this thread | | | Subject | Re: block-rbd: One function call less in rbd_dev_probe_parent() after error detection | From | SF Markus Elfring <> | Date | Thu, 26 Nov 2015 14:41:32 +0100 |
| |
>> * Why was the function "rbd_dev_probe_parent" implemented in the way >> that it relies on a sanity check in the function "rbd_dev_destroy" then? > > Because it's not a bad thing?
There are different opinions about this implementation detail.
> What's wrong with an init to NULL, a possible assignment, in this case > from rbd_dev_create(), and an unconditional rbd_dev_destroy()?
Does this approach look like it is affected by a "one error jump label bug" symptom?
> The NULL check in rbd_dev_destroy() is not a sanity check, > it's a feature.
I have got an other impression here.
> It's not there to "fixup" callers that pass NULL
It seems that the explanations on the detail why a function tolerates passed null pointers can also be different.
> - it's there because it is _expected_ that some callers will pass NULL.
I find it still unnecessary to let a called function like "rbd_dev_destroy" to repeat the check when you know already that the passed variable contains a null pointer.
> As I said in my reply to Dan, the problem with rbd_dev_probe_parent() > is the calling code which expects it to call unparent if ->parent_spec. > This makes it stand out and confuses people, but can't be fixed without > refactoring a bunch of other code.
I would appreciate if the discussed function could be also improved by itself. More refactoring might follow at other source code places later.
> The extra function call is *not* a problem.
How many software developers and reviewers will care if corresponding error handling can also become a bit more efficient?
Regards, Markus
| |