Re: [patch 23/39] PCI/MSI: Move pci_alloc_irq_vectors_affinity() to api.c

Bjorn Helgaas
2022-11-16T16:30:57Z

On Fri, Nov 11, 2022 at 02:54:51PM +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.
>
> Move pci_alloc_irq_vectors_affinity() and let its kernel-doc reference
> pci_alloc_irq_vectors() documentation added in parent commit.
>
> Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

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

One question below.

> ---
> drivers/pci/msi/api.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++-
> drivers/pci/msi/msi.c | 65 +----------------------------------------------------
> 2 files changed, 59 insertions(+), 65 deletions(-)
> ---
> diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c
> index 1714905943fb..8546749afa6e 100644
> --- a/drivers/pci/msi/api.c
> +++ b/drivers/pci/msi/api.c
> @@ -123,3 +123,62 @@ int pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
> flags, NULL);
> }
> EXPORT_SYMBOL(pci_alloc_irq_vectors);
> +
> +/**
> + * pci_alloc_irq_vectors_affinity() - Allocate multiple device interrupt
> + * vectors with affinity requirements
> + * @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: allocation flags, as in pci_alloc_irq_vectors()
> + * @affd: affinity requirements (can be %NULL).
> + *
> + * Same as pci_alloc_irq_vectors(), but with the extra @affd parameter.
> + * Check that function docs, and &struct irq_affinity, for more details.

Is "&struct irq_affinity" some kernel-doc syntax, or is the "&"
superfluous?

> + */
> +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)
> +{
> + struct irq_affinity msi_default_affd = {0};
> + int nvecs = -ENOSPC;
> +
> + if (flags & PCI_IRQ_AFFINITY) {
> + if (!affd)
> + affd = &msi_default_affd;
> + } else {
> + if (WARN_ON(affd))
> + affd = NULL;
> + }
> +
> + if (flags & PCI_IRQ_MSIX) {
> + nvecs = __pci_enable_msix_range(dev, NULL, min_vecs, max_vecs,
> + affd, flags);
> + if (nvecs > 0)
> + return nvecs;
> + }
> +
> + if (flags & PCI_IRQ_MSI) {
> + nvecs = __pci_enable_msi_range(dev, min_vecs, max_vecs, affd);
> + if (nvecs > 0)
> + return nvecs;
> + }
> +
> + /* use legacy IRQ if allowed */
> + if (flags & PCI_IRQ_LEGACY) {
> + if (min_vecs == 1 && dev->irq) {
> + /*
> + * Invoke the affinity spreading logic to ensure that
> + * the device driver can adjust queue configuration
> + * for the single interrupt case.
> + */
> + if (affd)
> + irq_create_affinity_masks(1, affd);
> + pci_intx(dev, 1);
> + return 1;
> + }
> + }
> +
> + return nvecs;
> +}
> +EXPORT_SYMBOL(pci_alloc_irq_vectors_affinity);
> diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
> index 6700ef1c734e..a028774f438d 100644
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -887,71 +887,6 @@ int __pci_enable_msix_range(struct pci_dev *dev,
> }
>
> /**
> - * pci_alloc_irq_vectors_affinity - allocate multiple IRQs for a device
> - * @dev: PCI device to operate on
> - * @min_vecs: minimum number of vectors required (must be >= 1)
> - * @max_vecs: maximum (desired) number of vectors
> - * @flags: flags or quirks for the allocation
> - * @affd: optional description of the affinity requirements
> - *
> - * Allocate up to @max_vecs interrupt vectors for @dev, using MSI-X or MSI
> - * vectors if available, and fall back to a single legacy vector
> - * if neither is available. Return the number of vectors allocated,
> - * (which might be smaller than @max_vecs) if successful, or a negative
> - * error code on error. If less than @min_vecs interrupt vectors are
> - * available for @dev the function will fail with -ENOSPC.
> - *
> - * To get the Linux IRQ number used for a vector that can be passed to
> - * request_irq() use the pci_irq_vector() helper.
> - */
> -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)
> -{
> - struct irq_affinity msi_default_affd = {0};
> - int nvecs = -ENOSPC;
> -
> - if (flags & PCI_IRQ_AFFINITY) {
> - if (!affd)
> - affd = &msi_default_affd;
> - } else {
> - if (WARN_ON(affd))
> - affd = NULL;
> - }
> -
> - if (flags & PCI_IRQ_MSIX) {
> - nvecs = __pci_enable_msix_range(dev, NULL, min_vecs, max_vecs,
> - affd, flags);
> - if (nvecs > 0)
> - return nvecs;
> - }
> -
> - if (flags & PCI_IRQ_MSI) {
> - nvecs = __pci_enable_msi_range(dev, min_vecs, max_vecs, affd);
> - if (nvecs > 0)
> - return nvecs;
> - }
> -
> - /* use legacy IRQ if allowed */
> - if (flags & PCI_IRQ_LEGACY) {
> - if (min_vecs == 1 && dev->irq) {
> - /*
> - * Invoke the affinity spreading logic to ensure that
> - * the device driver can adjust queue configuration
> - * for the single interrupt case.
> - */
> - if (affd)
> - irq_create_affinity_masks(1, affd);
> - pci_intx(dev, 1);
> - return 1;
> - }
> - }
> -
> - return nvecs;
> -}
> -EXPORT_SYMBOL(pci_alloc_irq_vectors_affinity);
> -
> -/**
> * pci_free_irq_vectors - free previously allocated IRQs for a device
> * @dev: PCI device to operate on
> *
>