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SubjectRe: [PATCH] of: Fix issue where code would fall through to error case.
On Mon, Nov 28, 2016 at 9:30 AM, Frank Rowand <frowand.list@gmail.com> wrote:
> On 11/26/16 13:39, Frank Rowand wrote:
>> On 11/23/16 13:58, Rob Herring wrote:
>>> On Thu, Nov 17, 2016 at 6:10 PM, Moritz Fischer
>>> <moritz.fischer.private@gmail.com> wrote:
>>>> On Thu, Nov 17, 2016 at 4:02 PM, Frank Rowand <frowand.list@gmail.com> wrote:
>>>>> On 11/17/16 15:40, Frank Rowand wrote:
>>>>>> On 11/17/16 15:25, Moritz Fischer wrote:
>>>>>>> No longer fall through into the error case that prints out
>>>>>>> an error if no error (err = 0) occurred.
>>>>>>>
>>>>>>> Fixes d9181b20a83(of: Add back an error message, restructured)
>>>>>>> Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>
>>>>>>> ---
>>>>>>> drivers/of/resolver.c | 6 +++++-
>>>>>>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>>>>>>
>>>>>>> diff --git a/drivers/of/resolver.c b/drivers/of/resolver.c
>>>>>>> index 783bd09..785076d 100644
>>>>>>> --- a/drivers/of/resolver.c
>>>>>>> +++ b/drivers/of/resolver.c
>>>>>>> @@ -358,9 +358,13 @@ int of_resolve_phandles(struct device_node *overlay)
>>>>>>>
>>>>>>> err = update_usages_of_a_phandle_reference(overlay, prop, phandle);
>>>>>>> if (err)
>>>>>>> - break;
>>>>>>> + goto err_out;
>>>>>>> }
>>>>>>>
>>>>>>> + of_node_put(tree_symbols);
>>>>>>> +
>>>>>>> + return 0;
>>>>>>> +
>>>>>>> err_out:
>>>>>>> pr_err("overlay phandle fixup failed: %d\n", err);
>>>>>>> out:
>>>>>>
>>>>>> Thanks for catching that.
>>>>>>
>>>>>> Rob, please apply.
>>>>>>
>>>>>> Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
>>>>>>
>>>>>> -Frank
>>>>>
>>>>> On second thought, isn't the common pattern when clean up is needed for
>>>>> both the no-error path and the error path something like:
>>>>>
>>>>>
>>>>> out:
>>>>> of_node_put(tree_symbols);
>>>>> return err;
>>>>>
>>>>> err_out:
>>>>> pr_err("overlay phandle fixup failed: %d\n", err);
>>>>> goto out;
>>>>> }
>>>>>
>>>>>
>>>>> I don't have a strong opinion, whatever Rob wants to take is fine with me.
>>>>
>>>> Same here. I tried to avoid the jumping back part, but if that's the
>>>> common pattern,
>>>> I can submit a v2 doing that instead.
>>>
>>> Both are ugly. Just do:
>>>
>>> if (err)
>>> pr_err(...);
>>>
>>> Rob
>>
>> Agreed. Thanks for the touch of sanity Rob.
>>
>> -Frank
>
> I succumbed to looking only at the few lines of code above and not the
> fuller context of the file that the patch applies to.
>
> The proposed patch was fixing the problem that a normal completion
> of the for loop was falling through into the err_out label. So what
> looks cleaner ("if (err) pr_err(...)") is actually not correct.

What!? The *only* problem was printing the error message in the err=0
case. All that needs to be fixed is not doing that. If we do that,
then we really only need 1 goto label.

Rob

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