[PATCH v2 1/7] PCI: aardvark: fix logic in PCI configuration read/write functions

[Bjorn Helgaas]

On Thu, Sep 28, 2017 at 02:58:32PM +0200, Thomas Petazzoni wrote:
> From: Victor Gu <xigu at marvell.com>
> 
> The PCI configuration space read/write functions were special casing
> the situation where PCI_SLOT(devfn) != 0, and returned
> PCIBIOS_DEVICE_NOT_FOUND in this case.
> 
> However, will this is what is intended for the root bus, it is not
> intended for the child busses, as it prevents discovering devices with
> PCI_SLOT(x) != 0. Therefore, we return PCIBIOS_DEVICE_NOT_FOUND only
> if we're on the root bus.
> 
> Fixes: 8c39d710363c1 ("PCI: aardvark: Add Aardvark PCI host controller driver")
> Cc: <stable at vger.kernel.org>
> Signed-off-by: Victor Gu <xigu at marvell.com>
> Reviewed-by: Wilson Ding <dingwei at marvell.com>
> Reviewed-by: Nadav Haklai <nadavh at marvell.com>
> [Thomas: tweak commit log.]
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
> ---
>  drivers/pci/host/pci-aardvark.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/host/pci-aardvark.c b/drivers/pci/host/pci-aardvark.c
> index 89f4e3d072d7..da2881ba7737 100644
> --- a/drivers/pci/host/pci-aardvark.c
> +++ b/drivers/pci/host/pci-aardvark.c
> @@ -440,7 +440,7 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
>  	u32 reg;
>  	int ret;
>  
> -	if (PCI_SLOT(devfn) != 0) {
> +	if ((bus->number == pcie->root_bus_nr) && (PCI_SLOT(devfn) != 0)) {

I'm fine with this, but please take a look at these:

  8e7ca8ca5fd8 PCI: xilinx: Relax device number checking to allow SR-IOV
  e18934b5e9c7 PCI: designware: Relax device number checking to allow SR-IOV
  d99e30b7936a PCI: altera: Relax device number checking to allow SR-IOV

and make sure that reasoning doesn't apply here, too.

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=8e7ca8ca5fd8
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=e18934b5e9c7
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=d99e30b7936a

>  		*val = 0xffffffff;
>  		return PCIBIOS_DEVICE_NOT_FOUND;
>  	}
> @@ -494,7 +494,7 @@ static int advk_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
>  	int offset;
>  	int ret;
>  
> -	if (PCI_SLOT(devfn) != 0)
> +	if ((bus->number == pcie->root_bus_nr) && (PCI_SLOT(devfn) != 0))
>  		return PCIBIOS_DEVICE_NOT_FOUND;
>  
>  	if (where % size)
> -- 
> 2.13.5
> 
> 
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