Re: [PATCH v7 1/4] PCI: Introduce pcim_alloc_irq_vectors()

Andy Shevchenko
2021-06-07T16:20:00Z

On Mon, Jun 07, 2021 at 11:39:13PM +0800, Dejin Zheng wrote:
> Introduce pcim_alloc_irq_vectors(), a device-managed version of
> pci_alloc_irq_vectors(). Introducing this function can simplify
> the error handling path in many drivers.
>
> And use pci_free_irq_vectors() to replace some code in pcim_release(),
> they are equivalent, and no functional change. It is more explicit
> that pcim_alloc_irq_vectors() is a device-managed function.

...

> When CONFIG_PCI=n, there is no stub for pci_is_managed(), but
> pcim_alloc_irq_vectors() will use it, so add one like other similar stubs.
> Otherwise there can be build errors, as here by kernel test robot
> reported:
> include/linux/pci.h: In function 'pcim_alloc_irq_vectors':
> >> include/linux/pci.h:1847:7: error: implicit declaration of function 'pci_is_managed' [-Werror=implicit-function-declaration]
> 1847 | if (!pci_is_managed(dev))
> | ^~~~~~~~~~~~~~

This is rather changelog related material. No need to pollute commit message
with this.

...

> Reported-by: kernel test robot <lkp@intel.com>

It's new functionality. Why this tag is here?
Use comments (similar location than changelog) to give a credit if you wish.

> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Reviewed-by: Robert Richter <rric@kernel.org>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Dejin Zheng <zhengdejin5@gmail.com>
> ---
> v6 -> v7:
> - rebase to PCI next branch
> - add a stub for pci_is_managed() when disable PCI for
> fix build error in sparc architecture.
> v5 -> v6:
> - rebase to 5.13-rc4
> v4 -> v5:
> - Remove the check of enable device in pcim_alloc_irq_vectors()
> and make it as a static line function.
> v3 -> v4:
> - No change
> v2 -> v3:
> - Add some commit comments for replace some codes in
> pcim_release() by pci_free_irq_vectors().
> v1 -> v2:
> - Use pci_free_irq_vectors() to replace some code in
> pcim_release().
> - Modify some commit messages.
>
> drivers/pci/pci.c | 5 +----
> include/linux/pci.h | 25 +++++++++++++++++++++++++
> 2 files changed, 26 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 452351025a09..e3b3fc59bd35 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -1989,10 +1989,7 @@ static void pcim_release(struct device *gendev, void *res)
> struct pci_devres *this = res;
> int i;
>
> - if (dev->msi_enabled)
> - pci_disable_msi(dev);
> - if (dev->msix_enabled)
> - pci_disable_msix(dev);
> + pci_free_irq_vectors(dev);
>
> for (i = 0; i < DEVICE_COUNT_RESOURCE; i++)
> if (this->region_mask & (1 << i))
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index c20211e59a57..5783262c4643 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1730,6 +1730,7 @@ static inline struct pci_dev *pci_get_class(unsigned int class,
>
> static inline void pci_set_master(struct pci_dev *dev) { }
> static inline int pci_enable_device(struct pci_dev *dev) { return -EIO; }
> +static inline int pci_is_managed(struct pci_dev *pdev) { return 0; }
> static inline void pci_disable_device(struct pci_dev *dev) { }
> static inline int pcim_enable_device(struct pci_dev *pdev) { return -EIO; }
> static inline int pci_assign_resource(struct pci_dev *dev, int i)
> @@ -1825,6 +1826,30 @@ pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
> NULL);
> }
>
> +/**
> + * pcim_alloc_irq_vectors - a device-managed pci_alloc_irq_vectors()
> + * @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
> + *
> + * 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.
> + *
> + * It depends on calling pcim_enable_device() to make IRQ resources
> + * manageable.
> + */
> +static inline int
> +pcim_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
> + unsigned int max_vecs, unsigned int flags)
> +{
> + if (!pci_is_managed(dev))
> + return -EINVAL;
> + return pci_alloc_irq_vectors(dev, min_vecs, max_vecs, flags);
> +}
> +
> /* Include architecture-dependent settings and functions */
>
> #include <asm/pci.h>
> --
> 2.30.1
>

--
With Best Regards,
Andy Shevchenko