[PATCH v2 01/11] powerpc/powernv/ioda: Fix ref count for devices with their own PE

[Michael Ellerman]

On Thu, 2019-11-21 at 13:49:08 UTC, Frederic Barrat wrote:
> The pci_dn structure used to store a pointer to the struct pci_dev, so
> taking a reference on the device was required. However, the pci_dev
> pointer was later removed from the pci_dn structure, but the reference
> was kept for the npu device.
> See commit 902bdc57451c ("powerpc/powernv/idoa: Remove unnecessary
> pcidev from pci_dn").
> 
> We don't need to take a reference on the device when assigning the PE
> as the struct pnv_ioda_pe is cleaned up at the same time as
> the (physical) device is released. Doing so prevents the device from
> being released, which is a problem for opencapi devices, since we want
> to be able to remove them through PCI hotplug.
> 
> Now the ugly part: nvlink npu devices are not meant to be
> released. Because of the above, we've always leaked a reference and
> simply removing it now is dangerous and would likely require more
> work. There's currently no release device callback for nvlink devices
> for example. So to be safe, this patch leaks a reference on the npu
> device, but only for nvlink and not opencapi.
> 
> CC: aik at ozlabs.ru
> CC: oohall at gmail.com
> Signed-off-by: Frederic Barrat <fbarrat at linux.ibm.com>

Series applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/05dd7da76986937fb288b4213b1fa10dbe0d1b33

cheers