Messages in this thread | | | Date | Wed, 22 Dec 2021 10:30:06 +0100 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH] nvmem: fix unregistering device in nvmem_register() error path |
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On Wed, Dec 22, 2021 at 10:16:20AM +0100, Rafał Miłecki wrote: > On 22.12.2021 10:08, Johan Hovold wrote: > > On Wed, Dec 22, 2021 at 10:00:03AM +0100, Rafał Miłecki wrote: > > > On 22.12.2021 09:38, Johan Hovold wrote: > > > > > > It seems Rafał is mistaken here too; you certainly need to call > > > > platform_device_put() if platform_device_register() fail, even if many > > > > current users do appear to get this wrong. > > > > > > Yes I was! Gosh I made up that "platform_device_put()" name and only > > > now I realized it actually exists! > > > > > > I stand by saying this design is really misleading. Even though > > > platform_device_put() was obviously a bad example. > > > > > > Please remember I'm just a minor kernel developer however in my humble > > > opinion behaviour of device_register() and platform_device_register() > > > should be changed. > > > > > > If any function fails I expect: > > > 1. That function to clean up its mess if any > > > 2. Me to be responsible to clean up my mess if any > > > > > > This is how "most" code (whatever it means) works. > > > 1. If POSIX snprintf() fails I'm not expected to call *printf_put() sth > > > 2. If POSIX bind() fails I'm not expected to call bind_put() sth > > > 3. (...) > > > > > > I'm not sure if those are the best examples but you should get my point. > > > > Yes, and we all agree that it's not the best interface. But it exists, > > and changing it now risks introducing worse problem than a minor, mostly > > theoretical, memleak. > > Thanks for confirming that, I was wondering if it's just my mind that > doesn't find this design clear enough. > > Now, assuming this design isn't perfect and some purists would like it > cleaned up: > > Would that make sense to introduce something like > 1. device_register2() / device_add2() > and > 2. platform_device_register2() / platform_device_add2() > > that would *not* require calling *_put() on failure? Then start > converting existing drivers to those new (clearner?) helpers?
See my other response, but no, this is not a good idea. device_register() is correct as-is, but platform_device_register() isn't.
thanks,
greg k-h
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