Re: [Xen-devel] [PATCH] xen: use PCI interfaces to request IO and MEM resources on platform device.

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

>>> On 11.01.11 at 12:50, Ian Campbell <ian.campbell@xxxxxxxxxx> wrote:
> This is the correct interface to use and something has broken the use
> of the previous incorrect interface (which fails because the request
> conflicts with the resources assigned for the PCI device itself
> instead of nesting like the PCI interfaces do).

While I agree that using the PCI interface is preferable, I can't see
how this can make a functional difference: __pci_request_region()
calls request_region() for the port resource and
__request_mem_region() for the mmio one exactly like what was
open coded before (request_mem_region() being equivalent to
__request_mem_region(..., 0), so I don't follow how this fixes
anything but half of the potentially incorrect use of "long" for
mmio_addr.

I'm mainly asking because if it really addresses some problem,
then unmodified_drivers/linux-2.6/platform-pci/platform-pci.c
in -unstable should probably get updated too.

Jan

> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxx # 2.6.37 only
> ---
>  drivers/xen/platform-pci.c |   21 +++++++--------------
>  1 files changed, 7 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/xen/platform-pci.c b/drivers/xen/platform-pci.c
> index c01b5dd..afbe041 100644
> --- a/drivers/xen/platform-pci.c
> +++ b/drivers/xen/platform-pci.c
> @@ -105,7 +105,7 @@ static int __devinit platform_pci_init(struct pci_dev 
> *pdev,
>                                      const struct pci_device_id *ent)
>  {
>       int i, ret;
> -     long ioaddr, iolen;
> +     long ioaddr;
>       long mmio_addr, mmio_len;
>       unsigned int max_nr_gframes;
>  
> @@ -114,7 +114,6 @@ static int __devinit platform_pci_init(struct pci_dev 
> *pdev,
>               return i;
>  
>       ioaddr = pci_resource_start(pdev, 0);
> -     iolen = pci_resource_len(pdev, 0);
>  
>       mmio_addr = pci_resource_start(pdev, 1);
>       mmio_len = pci_resource_len(pdev, 1);
> @@ -125,19 +124,13 @@ static int __devinit platform_pci_init(struct pci_dev 
> *pdev,
>               goto pci_out;
>       }
>  
> -     if (request_mem_region(mmio_addr, mmio_len, DRV_NAME) == NULL) {
> -             dev_err(&pdev->dev, "MEM I/O resource 0x%lx @ 0x%lx busy\n",
> -                    mmio_addr, mmio_len);
> -             ret = -EBUSY;
> +     ret = pci_request_region(pdev, 1, DRV_NAME);
> +     if (ret < 0)
>               goto pci_out;
> -     }
>  
> -     if (request_region(ioaddr, iolen, DRV_NAME) == NULL) {
> -             dev_err(&pdev->dev, "I/O resource 0x%lx @ 0x%lx busy\n",
> -                    iolen, ioaddr);
> -             ret = -EBUSY;
> +     ret = pci_request_region(pdev, 0, DRV_NAME);
> +     if (ret < 0)
>               goto mem_out;
> -     }
>  
>       platform_mmio = mmio_addr;
>       platform_mmiolen = mmio_len;
> @@ -169,9 +162,9 @@ static int __devinit platform_pci_init(struct pci_dev 
> *pdev,
>       return 0;
>  
>  out:
> -     release_region(ioaddr, iolen);
> +     pci_release_region(pdev, 0);
>  mem_out:
> -     release_mem_region(mmio_addr, mmio_len);
> +     pci_release_region(pdev, 1);
>  pci_out:
>       pci_disable_device(pdev);
>       return ret;





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