On Wed, Nov 14, 2018 at 1:05 PM Chanwoo Choi <cw00.choi@xxxxxxxxxxx> wrote: > On 2018년 11월 14일 19:20, Andy Shevchenko wrote: > > On Wed, Nov 14, 2018 at 11:48 AM Chanwoo Choi <cw00.choi@xxxxxxxxxxx> wrote: > >> On 2018년 11월 14일 18:36, Andy Shevchenko wrote: > >>> On Wed, Nov 14, 2018 at 06:13:37PM +0900, Chanwoo Choi wrote: > >>>> On 2018년 11월 14일 17:35, Andy Shevchenko wrote: > >>>>> On Wed, Nov 14, 2018 at 1:53 AM Chanwoo Choi <cw00.choi@xxxxxxxxxxx> wrote: > >>>>> > >>>>>> I was thinking about again to change from NULL to EPROBE_DEFER. > >>>>>> > >>>>>> extcon_get_extcon_dev() function was almost called in the probe function. > >>>>>> But, this function might be called on other position instead of probe. > >>>>> > >>>>> *Might be* sounds like a theoretical thing, care to share what is in you mind? > >>>>> Current users and more important the new coming one are *all* doing the same. > >>>>> > >>>>>> ENODEV is more correct error instead of EPROBE_DEFER. > >>>>> > >>>>> So, you are proposing to continue duplicating conversion from ENODEV > >>>>> to EPROBE_DEFER in *each* caller? > >>>> > >>>> The extcon core don't know the caller situation is in either probe() or other position > >>>> in the caller driver. The caller driver should decide the kind of error value > >>>> by using the return value of extcon_get_extcon_dev(). > >>>> > >>>> extcon_get_extcon_dev() function cannot be modified for only one case. > >>>> If some device driver call extcon_get_extcon_dev() out of probe() fuction, > >>>> EPROBE_DEFER is not always correct. > >>> > >>> I agree with this, but look at the current state of affairs. All users do the same. > >>> If we need to have another case we may consider this later. > >> > >> Because we know the potential wrong case of this change, I can't agree this change. > >> If extcon_get_extcon_dev() returns ENODEV instead of EPROBE_DEFER, > >> it is clear and then there are no problem on both current and future. > > > > Changing NULL to -ENODEV is a trading bad to worse. > > I would not go that way, so, it's your call. > > If you think that this change is not necessary, just keep the current code > without the modification. Not only this, the useless churn for no benefit to anyone, except some *theoretical* cases no one saw. > Please drop this patch on next version. I will. > >>> API inside the kernel are not carved in the stone. > > > > Only can repeat myself (see above). While I see *theoretical* > > rationale on your side, mine has *practical* proofs. > > So, I'm giving up on this and will duplicate same what it's done in 4 > > current callers. > > > > I think that it is more important for removing the potential wrong case > instead of removing the duplicate code. The many device drivers already > decided the proper error value by using the return value of function of > kernel framework. The API has been introduced back in 2012. commit 74c5d09bd562edc220d6e076b8f1e118819c178f Author: Donggeun Kim <dg77.kim@xxxxxxxxxxx> Date: Fri Apr 20 14:16:24 2012 +0900 So, you are insisting that 6.5 years of use in a way people are using it is wrong? I don't know what might change your mind, but for me it's a clear win-win to switch to deferred probe error code based on the *practical* evidence. But as I said, I gave up now. P.S. I still disagree with your arguments in relation to de facto use of an API. -- With Best Regards, Andy Shevchenko
