Re: [PATCH v2 1/3] PCI: Data corruption happening due to race condition

[Lukas Wunner <lukas@wunner.de>]

On Fri, Jun 29, 2018 at 03:57:39PM +0530, Hari Vyas wrote:
> Fix moves device addition is_added bit to separate private flag
> variable and use different atomic functions to set, clear and
> retrieve device addition state. As is_added shares different
> memory location so race condition is avoided.

As 0-day has already discovered, you need to squash all 3 patches
together to avoid breaking the build.


> +static inline int pci_dev_set_added(struct pci_dev *dev, void *unused)
> +{
> +	set_bit(PCI_DEV_ADDED, &dev->priv_flags);
> +	return 0;
> +}
> +
> +static inline int pci_dev_clear_added(struct pci_dev *dev, void *unused)
> +{
> +	clear_bit(PCI_DEV_ADDED, &dev->priv_flags);
> +	return 0;
> +}

You don't need the "unused" parameter here and you can return void.
pci_dev_set_disconnected() has the parameter because the function is
passed in to pci_walk_bus() in a few places, but you're not doing that
AFAICS.

What you *could* do however is collapse pci_dev_set_added() and
pci_dev_clear_added() into a single function, pass in a bool "added",
then use assign_bit() to set or clear it.  It would save 6 LoC.

Thanks,

Lukas