Re: [patch RFC 13/38] PCI: MSI: Rework pci_msi_domain_calc_hwirq()

Bjorn Helgaas
2020-08-25T20:03:35Z

On Fri, Aug 21, 2020 at 02:24:37AM +0200, Thomas Gleixner wrote:
> Retrieve the PCI device from the msi descriptor instead of doing so at the
> call sites.

I'd like it *better* with "PCI/MSI: " in the subject (to match history
and other patches in this series) and "MSI" here in the commit log,
but nice cleanup and:

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

Minor comments below.

> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: linux-pci@vger.kernel.org
> ---
> arch/x86/kernel/apic/msi.c | 2 +-
> drivers/pci/msi.c | 13 ++++++-------
> include/linux/msi.h | 3 +--
> 3 files changed, 8 insertions(+), 10 deletions(-)
>
> --- a/arch/x86/kernel/apic/msi.c
> +++ b/arch/x86/kernel/apic/msi.c
> @@ -232,7 +232,7 @@ EXPORT_SYMBOL_GPL(pci_msi_prepare);
>
> void pci_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
> {
> - arg->msi_hwirq = pci_msi_domain_calc_hwirq(arg->msi_dev, desc);
> + arg->msi_hwirq = pci_msi_domain_calc_hwirq(desc);

I guess it's safe to assume that "arg->msi_dev ==
msi_desc_to_pci_dev(desc)"? I didn't try to verify that.

> }
> EXPORT_SYMBOL_GPL(pci_msi_set_desc);
>
> --- a/drivers/pci/msi.c
> +++ b/drivers/pci/msi.c
> @@ -1346,17 +1346,17 @@ void pci_msi_domain_write_msg(struct irq
>
> /**
> * pci_msi_domain_calc_hwirq - Generate a unique ID for an MSI source
> - * @dev: Pointer to the PCI device
> * @desc: Pointer to the MSI descriptor
> *
> * The ID number is only used within the irqdomain.
> */
> -irq_hw_number_t pci_msi_domain_calc_hwirq(struct pci_dev *dev,
> - struct msi_desc *desc)
> +irq_hw_number_t pci_msi_domain_calc_hwirq(struct msi_desc *desc)
> {
> + struct pci_dev *pdev = msi_desc_to_pci_dev(desc);

If you named this "struct pci_dev *dev" (not "pdev"), the diff would
be a little smaller and it would match other usage in the file.

> return (irq_hw_number_t)desc->msi_attrib.entry_nr |
> - pci_dev_id(dev) << 11 |
> - (pci_domain_nr(dev->bus) & 0xFFFFFFFF) << 27;
> + pci_dev_id(pdev) << 11 |
> + (pci_domain_nr(pdev->bus) & 0xFFFFFFFF) << 27;
> }
>
> static inline bool pci_msi_desc_is_multi_msi(struct msi_desc *desc)
> @@ -1406,8 +1406,7 @@ static void pci_msi_domain_set_desc(msi_
> struct msi_desc *desc)
> {
> arg->desc = desc;
> - arg->hwirq = pci_msi_domain_calc_hwirq(msi_desc_to_pci_dev(desc),
> - desc);
> + arg->hwirq = pci_msi_domain_calc_hwirq(desc);
> }
> #else
> #define pci_msi_domain_set_desc NULL
> --- a/include/linux/msi.h
> +++ b/include/linux/msi.h
> @@ -369,8 +369,7 @@ void pci_msi_domain_write_msg(struct irq
> struct irq_domain *pci_msi_create_irq_domain(struct fwnode_handle *fwnode,
> struct msi_domain_info *info,
> struct irq_domain *parent);
> -irq_hw_number_t pci_msi_domain_calc_hwirq(struct pci_dev *dev,
> - struct msi_desc *desc);
> +irq_hw_number_t pci_msi_domain_calc_hwirq(struct msi_desc *desc);
> int pci_msi_domain_check_cap(struct irq_domain *domain,
> struct msi_domain_info *info, struct device *dev);
> u32 pci_msi_domain_get_msi_rid(struct irq_domain *domain, struct pci_dev *pdev);
>