On Wed, Jul 02, 2014 at 09:43:41PM +0100, Tanmay Inamdar wrote:

On Wed, Jul 2, 2014 at 12:12 PM, Arnd Bergmann [off-list ref] wrote:

quoted

On Wednesday 02 July 2014 11:06:38 Tanmay Inamdar wrote:

quoted

On Tue, Jul 1, 2014 at 11:43 AM, Liviu Dudau [off-list ref] wrote:

quoted

This is a useful function and we should make it visible outside the
generic PCI code. Export it as a GPL symbol.

Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Tested-by: Tanmay Inamdar <redacted>
---
 drivers/pci/host-bridge.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index 0e5f3c9..36c669e 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c

@@ -16,12 +16,13 @@ static struct pci_bus *find_pci_root_bus(struct pci_bus *bus)
        return bus;
 }

-static struct pci_host_bridge *find_pci_host_bridge(struct pci_bus *bus)
+struct pci_host_bridge *find_pci_host_bridge(struct pci_bus *bus)
 {
        struct pci_bus *root_bus = find_pci_root_bus(bus);

        return to_pci_host_bridge(root_bus->bridge);
 }
+EXPORT_SYMBOL_GPL(find_pci_host_bridge);

Is there any specific reason behind making this symbol GPL? I think
the other functions in this file are just EXPORT_SYMBOL. Ultimately
companies which have non gpl Linux modules (nvidia) will face issue
using this API.

The same applies to 'of_create_pci_host_bridge'.

I think EXPORT_SYMBOL_GPL() is better here. The new symbols are unlikely
to be used by a peripheral device driver, and PCI host controllers are
already restricted by EXPORT_SYMBOL_GPL.

You are right as long as the functions are not used directly. But what
if GPL functions are called indirectly.  For example, 'pci_domain_nr'
implementation in Liviu's V7 series calls 'find_pci_host_bridge'.

I will not be drawn into the discussion of EXPORT_SYMBOL vs EXPORT_SYMBOL_GPL()
other than to say that I don't understand what is so secret in implementing
a standard. I do not want to support host bridge drivers that are not open
source.

Best regards,
Liviu

quoted

nvidia will certainly not do a PCI host controller driver that is not
upstream or not GPL-compatible.

        Arnd

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