Re: [patch 19/39] PCI/MSI: Move pci_disable_msi() to api.c

Bjorn Helgaas
2022-11-16T16:16:43Z

On Fri, Nov 11, 2022 at 02:54:45PM +0100, Thomas Gleixner wrote:
> From: Ahmed S. Darwish <darwi@linutronix.de>
>
> msi.c is a maze of randomly sorted functions which makes the code
> unreadable. As a first step split the driver visible API and the internal
> implementation which also allows proper API documentation via one file.
>
> Create drivers/pci/msi/api.c to group all exported device-driver PCI/MSI
> APIs in one C file.
>
> Begin by moving pci_disable_msi() there and add kernel-doc for the function
> as appropriate.
>
> Suggested-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

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

> ---
> drivers/pci/msi/Makefile | 3 +--
> drivers/pci/msi/api.c | 37 +++++++++++++++++++++++++++++++++++++
> drivers/pci/msi/msi.c | 22 +++++-----------------
> drivers/pci/msi/msi.h | 4 ++++
> 4 files changed, 47 insertions(+), 19 deletions(-)
> create mode 100644 drivers/pci/msi/api.c
> ---
> diff --git a/drivers/pci/msi/Makefile b/drivers/pci/msi/Makefile
> index 4e0a7e07965e..839ff72d72a8 100644
> --- a/drivers/pci/msi/Makefile
> +++ b/drivers/pci/msi/Makefile
> @@ -2,6 +2,5 @@
> #
> # Makefile for the PCI/MSI
> obj-$(CONFIG_PCI) += pcidev_msi.o
> -obj-$(CONFIG_PCI_MSI) += msi.o
> -obj-$(CONFIG_PCI_MSI) += irqdomain.o
> +obj-$(CONFIG_PCI_MSI) += api.o msi.o irqdomain.o
> obj-$(CONFIG_PCI_MSI_ARCH_FALLBACKS) += legacy.o
> diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c
> new file mode 100644
> index 000000000000..7485942cbe5d
> --- /dev/null
> +++ b/drivers/pci/msi/api.c
> @@ -0,0 +1,37 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PCI MSI/MSI-X — Exported APIs for device drivers
> + *
> + * Copyright (C) 2003-2004 Intel
> + * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
> + * Copyright (C) 2016 Christoph Hellwig.
> + * Copyright (C) 2022 Linutronix GmbH
> + */
> +
> +#include <linux/export.h>
> +
> +#include "msi.h"
> +
> +/**
> + * pci_disable_msi() - Disable MSI interrupt mode on device
> + * @dev: the PCI device to operate on
> + *
> + * Legacy device driver API to disable MSI interrupt mode on device,
> + * free earlier allocated interrupt vectors, and restore INTx emulation.
> + * The PCI device Linux IRQ (@dev->irq) is restored to its default
> + * pin-assertion IRQ. This is the cleanup pair of pci_enable_msi().
> + *
> + * NOTE: The newer pci_alloc_irq_vectors() / pci_free_irq_vectors() API
> + * pair should, in general, be used instead.
> + */
> +void pci_disable_msi(struct pci_dev *dev)
> +{
> + if (!pci_msi_enabled() || !dev || !dev->msi_enabled)
> + return;
> +
> + msi_lock_descs(&dev->dev);
> + pci_msi_shutdown(dev);
> + pci_free_msi_irqs(dev);
> + msi_unlock_descs(&dev->dev);
> +}
> +EXPORT_SYMBOL(pci_disable_msi);
> diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
> index 5c310df55d0d..4a1300b74518 100644
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -163,7 +163,7 @@ void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg)
> }
> EXPORT_SYMBOL_GPL(pci_write_msi_msg);
>
> -static void free_msi_irqs(struct pci_dev *dev)
> +void pci_free_msi_irqs(struct pci_dev *dev)
> {
> pci_msi_teardown_msi_irqs(dev);
>
> @@ -413,7 +413,7 @@ static int msi_capability_init(struct pci_dev *dev, int nvec,
>
> err:
> pci_msi_unmask(entry, msi_multi_mask(entry));
> - free_msi_irqs(dev);
> + pci_free_msi_irqs(dev);
> fail:
> dev->msi_enabled = 0;
> unlock:
> @@ -531,7 +531,7 @@ static int msix_setup_interrupts(struct pci_dev *dev, void __iomem *base,
> goto out_unlock;
>
> out_free:
> - free_msi_irqs(dev);
> + pci_free_msi_irqs(dev);
> out_unlock:
> msi_unlock_descs(&dev->dev);
> kfree(masks);
> @@ -680,7 +680,7 @@ int pci_msi_vec_count(struct pci_dev *dev)
> }
> EXPORT_SYMBOL(pci_msi_vec_count);
>
> -static void pci_msi_shutdown(struct pci_dev *dev)
> +void pci_msi_shutdown(struct pci_dev *dev)
> {
> struct msi_desc *desc;
>
> @@ -701,18 +701,6 @@ static void pci_msi_shutdown(struct pci_dev *dev)
> pcibios_alloc_irq(dev);
> }
>
> -void pci_disable_msi(struct pci_dev *dev)
> -{
> - if (!pci_msi_enable || !dev || !dev->msi_enabled)
> - return;
> -
> - msi_lock_descs(&dev->dev);
> - pci_msi_shutdown(dev);
> - free_msi_irqs(dev);
> - msi_unlock_descs(&dev->dev);
> -}
> -EXPORT_SYMBOL(pci_disable_msi);
> -
> /**
> * pci_msix_vec_count - return the number of device's MSI-X table entries
> * @dev: pointer to the pci_dev data structure of MSI-X device function
> @@ -797,7 +785,7 @@ void pci_disable_msix(struct pci_dev *dev)
>
> msi_lock_descs(&dev->dev);
> pci_msix_shutdown(dev);
> - free_msi_irqs(dev);
> + pci_free_msi_irqs(dev);
> msi_unlock_descs(&dev->dev);
> }
> EXPORT_SYMBOL(pci_disable_msix);
> diff --git a/drivers/pci/msi/msi.h b/drivers/pci/msi/msi.h
> index d8f62d911f08..634879277349 100644
> --- a/drivers/pci/msi/msi.h
> +++ b/drivers/pci/msi/msi.h
> @@ -84,6 +84,10 @@ static inline __attribute_const__ u32 msi_multi_mask(struct msi_desc *desc)
> return (1 << (1 << desc->pci.msi_attrib.multi_cap)) - 1;
> }
>
> +/* MSI internal functions invoked from the public APIs */
> +void pci_msi_shutdown(struct pci_dev *dev);
> +void pci_free_msi_irqs(struct pci_dev *dev);
> +
> /* Legacy (!IRQDOMAIN) fallbacks */
> #ifdef CONFIG_PCI_MSI_ARCH_FALLBACKS
> int pci_msi_legacy_setup_msi_irqs(struct pci_dev *dev, int nvec, int type);
>