Re: [RFC 1/4] PCI: Add hooks to allocate/free IRQ resources when binding/unbinding driver

[Bjorn Helgaas <bhelgaas@google.com>]

On Thu, May 07, 2015 at 11:12:51AM +0800, Jiang Liu wrote:
> Add two hook points pcibios_{alloc|free}_irq() into PCI core, which will
> be called when binding/unbinding PCI device drivers. Then PCI arch code
> may hook into these two points to allocate IRQ resources on demand and
> free them when not used anymore.
> 
> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> ---
>  drivers/pci/pci-driver.c |   33 +++++++++++++++++++++++----------
>  include/linux/pci.h      |    2 ++
>  2 files changed, 25 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 3cb2210de553..8af4a671686f 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> ...
> +static int pci_device_probe(struct device *dev)
> +{
> +	int error;
> +	struct pci_dev *pci_dev = to_pci_dev(dev);
> +	struct pci_driver *drv = to_pci_driver(dev->driver);
> +
> +	error = pcibios_alloc_irq(pci_dev);
> +	if (error >= 0) {
> +		pci_dev_get(pci_dev);
> +		error = __pci_device_probe(drv, pci_dev);
> +		if (error) {
> +			pcibios_free_irq(pci_dev);
> +			pci_dev_put(pci_dev);
> +		}
> +	}

Please structure it like this so the mainline code doesn't get buried in
the body of the "if":

    irq = pcibios_alloc_irq(pci_dev);
    if (irq < 0)
	return irq;

    pci_dev_get(pci_dev);
    ...

>  
>  	return error;
>  }