Re: [PATCH v2] PCI: Provide pci_free_irq_vectors() for CONFIG_PCI=n

[Boqun Feng <boqun.feng@gmail.com>]

On Fri, Dec 26, 2025 at 07:39:38PM +0800, Boqun Feng wrote:
> Commit 473b9f331718 ("rust: pci: fix build failure when CONFIG_PCI_MSI
> is disabled") fixed a build error by providing rust helpers when
> CONFIG_PCI_MSI=n. However the rust helpers rely on the
> pci_alloc_irq_vectors() function is defined, which is not true when
> CONFIG_PCI=n. There are multiple ways to fix this, e.g. a possible fix
> could be just remove the calling of pci_alloc_irq_vectors() since it's
> empty when CONFIG_PCI_MSI=n anyway. However, since PCI irq APIs, such as
> pci_alloc_irq_vectors(), are already defined even when CONFIG_PCI=n, the
> more reasonable fix is to define pci_alloc_irq_vectors() when
> CONFIG_PCI=n and this aligns with the situations of other primitives as
> well.
> 

Ping ;-) Bjorn, would it be possible to take via pci tree? Thanks!

Regards,
Boqun

> Reported-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
> Closes: https://lore.kernel.org/rust-for-linux/20251209014312.575940-1-fujita.tomonori@gmail.com/
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202512220740.4Kexm4dW-lkp@intel.com/
> Reported-by: Liang Jie <liangjie@lixiang.com>
> Closes: https://lore.kernel.org/rust-for-linux/20251222034415.1384223-1-buaajxlj@163.com/
> Fixes: 473b9f331718 ("rust: pci: fix build failure when CONFIG_PCI_MSI is disabled")
> Reviewed-by: Drew Fustini <fustini@kernel.org>
> Reviewed-by: David Gow <davidgow@google.com>
> Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
> Reviewed-by: Danilo Krummrich <dakr@kernel.org>
> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
> ---
> v1 --> v2:
> 
> * Add Reported-by from FUJITA Tomonori, kernel test robot and Liang Jie.
> * Add Reviewed-by tags.
> 
> Thanks!
> 
> Liang Jie, I added you as Reported-by because of [1], if you prefer not
> to have that tag, feel free to let me know, thanks!
> 
> [1]: https://lore.kernel.org/rust-for-linux/20251222034415.1384223-1-buaajxlj@163.com/
> 
>  include/linux/pci.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index 864775651c6f..b5cc0c2b9906 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -2210,6 +2210,10 @@ pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
>  {
>  	return -ENOSPC;
>  }
> +
> +static inline void pci_free_irq_vectors(struct pci_dev *dev)
> +{
> +}
>  #endif /* CONFIG_PCI */
>  
>  /* Include architecture-dependent settings and functions */
> -- 
> 2.51.0
>