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SubjectRe: [PATCH v2] PCI/MSI: Simplify the return value of arch_setup_msi_irqs
On Wed, Jun 22, 2016 at 11:20:20AM +0800, Shawn Lin wrote:
> No any callers do care whether arch_setup_msi_irqs returns
> -ENOSPC or other error numbers. That means they treat the
> negative numbers in the same way. So there shouldn't make any
> difference to directly return -ENOSPC if finding it's non-zero.

This return value gets returned all the way up to the external
interfaces used by drivers, e.g., pci_enable_msi_range(), so it would
take quite a lot of analysis to assert that *no* caller cares whether
it's -ENOSPC or something else. I suspect you're right that it
probably doesn't matter, but it looks pretty hard to prove it.

> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
>
> ---
>
> Changes in v2:
> - fix warning generated by -Wmisleading-indentation reported by Kbuild robot
>
> drivers/pci/msi.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
> index a080f44..5057219 100644
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -108,7 +108,7 @@ int __weak arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
> {
> struct msi_controller *chip = dev->bus->msi;
> struct msi_desc *entry;
> - int ret;
> + int ret = 0;

I don't think this initialization is necessary.

> if (chip && chip->setup_irqs)
> return chip->setup_irqs(chip, dev, nvec, type);
> @@ -121,9 +121,7 @@ int __weak arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
>
> for_each_pci_msi_entry(entry, dev) {
> ret = arch_setup_msi_irq(dev, entry);
> - if (ret < 0)
> - return ret;
> - if (ret > 0)
> + if (ret)
> return -ENOSPC;
> }
>
> --
> 2.3.7
>
>
> --
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