On Fri, 2022-04-22 at 15:28 +0200, Niklas Schnelle wrote:
> While determining the next PCI function is factored out of
> pci_scan_slot() into next_fn() the former still handles the first
> function as a special case. This duplicates the code from the scan loop.
>
> Furthermore the non ARI branch of next_fn() is generally hard to
> understand and especially the check for multifunction devices is hidden
> in the handling of NULL devices for non-contiguous multifunction. It
> also signals that no further functions need to be scanned by returning
> 0 via wraparound and this is a valid function number.
>
> Improve upon this by transforming the conditions in next_fn() to be
> easier to understand.
>
> By changing next_fn() to return -ENODEV instead of 0 when there is no
> next function we can then handle the initial function inside the loop
> and deduplicate the shared handling. This also makes it more explicit
> that only function 0 must exist.
>
> No functional change is intended.
>
> Cc: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
> Signed-off-by: Niklas Schnelle <schnelle@xxxxxxxxxxxxx>
> ---
> drivers/pci/probe.c | 39 ++++++++++++++++++++-------------------
> 1 file changed, 20 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 17a969942d37..2000e9858f12 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -2579,8 +2579,7 @@ struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn)
> }
> EXPORT_SYMBOL(pci_scan_single_device);
>
> -static unsigned int next_fn(struct pci_bus *bus, struct pci_dev *dev,
> - unsigned int fn)
> +static int next_fn(struct pci_bus *bus, struct pci_dev *dev, int fn)
> {
> int pos;
> u16 cap = 0;
> @@ -2588,24 +2587,27 @@ static unsigned int next_fn(struct pci_bus *bus, struct pci_dev *dev,
>
> if (pci_ari_enabled(bus)) {
> if (!dev)
> - return 0;
> + return -ENODEV;
> +
>
Sorry the whitespace damage was of course not intended, fixed locally.
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