On Fri, May 17, 2019 at 12:03:12PM +0100, Jeremy Sowden wrote:
> The call-backs used the same recipe to get the pcard from dev:
>
> struct pci_dev *pdev = to_pci_dev(dev);
> struct kp2000_device *pcard;
>
> if (!pdev) return -ENXIO;
> pcard = pci_get_drvdata(pdev);
> if (!pcard) return -ENXIO;
>
> where to_pci_dev is a wrapper for container_of.
>
> However, pci_set_drvdata is called before the sysfs files are created:
>
> int kp2000_pcie_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> {
> // ...
>
> pcard = kzalloc(sizeof(struct kp2000_device), GFP_KERNEL);
>
> // ...
>
> pcard->pdev = pdev;
> pci_set_drvdata(pdev, pcard);
>
> // ...
>
> err = sysfs_create_files(&(pdev->dev.kobj), kp_attr_list);
>
> Therefore, to_pci_dev and pci_get_drvdata cannot return NULL, and pcard
> can be initialized directly from dev:
>
> struct kp2000_device *pcard = dev_get_drvdata(dev);
>
> Signed-off-by: Jeremy Sowden <jer...@azazel.net>
> ---
> drivers/staging/kpc2000/kpc2000/core.c | 24 +++---------------------
> 1 file changed, 3 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/staging/kpc2000/kpc2000/core.c
> b/drivers/staging/kpc2000/kpc2000/core.c
> index eb8bac62d33d..9425c4dbc2f2 100644
> --- a/drivers/staging/kpc2000/kpc2000/core.c
> +++ b/drivers/staging/kpc2000/kpc2000/core.c
> @@ -24,12 +24,7 @@
> ******************************************************/
> static ssize_t show_attr(struct device *dev, struct device_attribute *attr,
> char *buf)
> {
> - struct pci_dev *pdev = to_pci_dev(dev);
> - struct kp2000_device *pcard;
> -
> - if (!pdev) return -ENXIO;
> - pcard = pci_get_drvdata(pdev);
> - if (!pcard) return -ENXIO;
> + struct kp2000_device *pcard = dev_get_drvdata(dev);
Wait, dev_get_drvdata() is not returning you the same pointer that
pci_get_drvdata() does. So I think this is now broken :(
What this should look like is this:
struct pci_dev *pdev = to_pci_dev(dev);
struct kp200_device *pcard = pci_get_drvdata(pdev);
if (!pcard)
return -ENODEV;
that is IF the driver really is setting the pci dev data to NULL when
the device is removed from the driver. Is it?
thanks,
greg k-h
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