Re: [patch 22/39] PCI/MSI: Move pci_alloc_irq_vectors() to api.c

Bjorn Helgaas
2022-11-16T16:25:30Z

On Fri, Nov 11, 2022 at 02:54:50PM +0100, Thomas Gleixner wrote:
> From: Ahmed S. Darwish <darwi@linutronix.de>
>
> To distangle the maze in msi.c, all exported device-driver MSI APIs are
> now to be grouped in one file, api.c.
>
> Make pci_alloc_irq_vectors() a real function instead of wrapper and add
> proper kernel doc to it.
>
> Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

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

Two nits below.

> ---
> drivers/pci/msi/api.c | 33 +++++++++++++++++++++++++++++++++
> include/linux/pci.h | 17 +++++++++--------
> 2 files changed, 42 insertions(+), 8 deletions(-)
> ---
> diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c
> index d48050555d55..1714905943fb 100644
> --- a/drivers/pci/msi/api.c
> +++ b/drivers/pci/msi/api.c
> @@ -90,3 +90,36 @@ int pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries,
> return __pci_enable_msix_range(dev, entries, minvec, maxvec, NULL, 0);
> }
> EXPORT_SYMBOL(pci_enable_msix_range);
> +
> +/**
> + * pci_alloc_irq_vectors() - Allocate multiple device interrupt vectors
> + * @dev: the PCI device to operate on
> + * @min_vecs: minimum required number of vectors (must be >= 1)
> + * @max_vecs: maximum desired number of vectors
> + * @flags: One or more of:
> + * %PCI_IRQ_MSIX Allow trying MSI-X vector allocations
> + * %PCI_IRQ_MSI Allow trying MSI vector allocations
> + * %PCI_IRQ_LEGACY Allow trying legacy INTx interrupts, if
> + * and only if @min_vecs == 1
> + * %PCI_IRQ_AFFINITY Auto-manage IRQs affinity by spreading
> + * the vectors around available CPUs
> + *
> + * Allocate up to @max_vecs interrupt vectors on device. MSI-X irq

s/irq/IRQ/

> + * vector allocation has a higher precedence over plain MSI, which has a
> + * higher precedence over legacy INTx emulation.
> + *
> + * Upon a successful allocation, the caller should use pci_irq_vector()
> + * to get the Linux IRQ number to be passed to request_threaded_irq().
> + * The driver must call pci_free_irq_vectors() on cleanup.
> + *
> + * Return: number of allocated vectors (which might be smaller than
> + * @max_vecs), -ENOSPC if less than @min_vecs interrupt vectors are

s/less/fewer/ (also in some previous patches, IIRC)

> + * available, other errnos otherwise.
> + */
> +int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
> + unsigned int max_vecs, unsigned int flags)
> +{
> + return pci_alloc_irq_vectors_affinity(dev, min_vecs, max_vecs,
> + flags, NULL);
> +}
> +EXPORT_SYMBOL(pci_alloc_irq_vectors);
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 2bda4a4e47e8..6a356a39ba94 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1553,6 +1553,8 @@ static inline int pci_enable_msix_exact(struct pci_dev *dev,
> return rc;
> return 0;
> }
> +int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
> + unsigned int max_vecs, unsigned int flags);
> int pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
> unsigned int max_vecs, unsigned int flags,
> struct irq_affinity *affd);
> @@ -1586,6 +1588,13 @@ pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
> return 1;
> return -ENOSPC;
> }
> +static inline int
> +pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
> + unsigned int max_vecs, unsigned int flags)
> +{
> + return pci_alloc_irq_vectors_affinity(dev, min_vecs, max_vecs,
> + flags, NULL);
> +}
>
> static inline void pci_free_irq_vectors(struct pci_dev *dev)
> {
> @@ -1900,14 +1909,6 @@ pci_alloc_irq_vectors_affinity(struct pci_dev *dev, unsigned int min_vecs,
> }
> #endif /* CONFIG_PCI */
>
> -static inline int
> -pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
> - unsigned int max_vecs, unsigned int flags)
> -{
> - return pci_alloc_irq_vectors_affinity(dev, min_vecs, max_vecs, flags,
> - NULL);
> -}
> -
> /* Include architecture-dependent settings and functions */
>
> #include <asm/pci.h>
>