On Fri, Sep 14, 2018 at 02:23:51PM +0100, Robin Murphy wrote: > On 13/09/18 16:17, Wolfram Sang wrote: > > While sanitizig the pointer for dma_ops on teardown, do the same for > > dma_parms, too. Rename the function to have a more generic name. > > Upon closer inspection, it looks like there are some cases (at least PCI and > MFD) where dma_parms is installed by the parent/bus at device creation, and > therefore remains valid and *would* be expected to persist across the child > device's driver unbinding and rebinding - seems this is more complex than I > first thought, sorry. No problem. I am thankful I understand more details. So, the life cycle of dma_parms is truly that of the device. Which means that the drivers using devm_kzalloc in their probe, should ideally clear the pointer on unbind. Otherwise, it is not possible to say if the non-NULL dma_parms is intended or dangling. Which makes my initial dmam_set_dma_parms() approach look not too bad, I'd think? However, I don't want to push hard with this one. If you think this is too academic, I'll just leave it for now...
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