Re: [PATCH 0/7] Fixups for duplicate slot names

[Kenji Kaneshige]

Alex Chiang wrote:
> * Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>:
> > Hi Alex-san,
> >
> > Thank you for patches!
> >
> > I looked at your patches and it looks good. But I have only one
> > concern about how to allocate/free memory for slot name.
> >
> > With your change, memory region for slot name will be allocated
> > by hotplug *controller* driver and it can be freed using kfree()
> > by hotplug *core* driver (not hotplug controller driver). So all
> > hotplug controller drivers including drivers implemented in the
> > future need to take it into account.
> >
> > I think it will be more robust if we can allocate and free memory
> > in the same component (maybe hotplug core driver in this case).
>
> Hm, I didn't think this would be a problem. The sequence is:
>
> 	- controller allocates memory for slot name
> 	- if core detects a collision:
> 		- it frees the name
> 		- it allocates new memory for name
> 		- it assigns that memory to the name parameter
> 	- controller->release will eventually free the name
>
> So it shouldn't matter if the core frees the original name
> pointer and allocates new memory, because the core will change
> the pointer for the controller.
>
> This is why I had to change the interface of pci_create_slot()
> from taking a const char *name to a char *name.
>
> Is there something I'm missing?
>
> /ac

I'm worrying about the following cases for example:

- hotplug controller driver allocates memory for slot name using
  other than kmalloc().

- hotplug controller driver allocates memory for slot name as
  a part of another data structure.

Thanks,
Kenji Kaneshige


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