[v7] powerpc/pci: Assign fixed PHB number based on device-tree properties

[Michael Ellerman]

On Wed, 2016-29-06 at 18:14:22 UTC, "Guilherme G. Piccoli" wrote:
> The domain/PHB field of PCI addresses has its value obtained from a
> global variable, incremented each time a new domain (represented by
> struct pci_controller) is added on the system. The domain addition
> process happens during boot or due to PHB hotplug add.
> 
> As recent kernels are using predictable naming for network interfaces,
> the network stack is more tied to PCI naming. This can be a problem in
> hotplug scenarios, because PCI addresses will change if devices are
> removed and then re-added. This situation seems unusual, but it can
> happen if a user wants to replace a NIC without rebooting the machine,
> for example.
> 
> This patch changes the way PCI domain values are generated: now, we use
> device-tree properties to assign fixed PHB numbers to PCI addresses
> when available (meaning pSeries and PowerNV cases). We also use a bitmap
> to allow dynamic PHB numbering when device-tree properties are not
> used. This bitmap keeps track of used PHB numbers and if a PHB is
> released (by hotplug operations for example), it allows the reuse of
> this PHB number, avoiding PCI address to change in case of device remove
> and re-add soon after. No functional changes were introduced.
> 
> Signed-off-by: Guilherme G. Piccoli <gpiccoli at linux.vnet.ibm.com>
> Reviewed-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
> Reviewed-by: Ian Munsie <imunsie at au1.ibm.com>
> Acked-by: Gavin Shan <gwshan at linux.vnet.ibm.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/63a72284b159c569ec52f380c9

cheers