[tip: irq/urgent] PCI/MSI: Provide missing stubs for CONFIG_PCI_MSI=n

[tip-bot2 for Reinette Chatre]

The following commit has been merged into the irq/urgent branch of tip:

Commit-ID:     2b129f0b24ab578b02901b4a1744b7f97399faa0
Gitweb:        https://git.kernel.org/tip/2b129f0b24ab578b02901b4a1744b7f97399faa0
Author:        Reinette Chatre <reinette.chatre@xxxxxxxxx>
AuthorDate:    Thu, 09 Feb 2023 13:49:00 -08:00
Committer:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Mon, 13 Feb 2023 12:17:20 +01:00

PCI/MSI: Provide missing stubs for CONFIG_PCI_MSI=n

pci_msix_alloc_irq_at() and pci_msix_free_irq() are not declared when
CONFIG_PCI_MSI is disabled.

Users of these two calls do not yet exist but when users do appear (shown
below is an attempt to use the new API in vfio-pci) the following errors
will be encountered when compiling with CONFIG_PCI_MSI disabled:

drivers/vfio/pci/vfio_pci_intrs.c:461:4: error: implicit declaration of\
        function 'pci_msix_free_irq' is invalid in C99\
        [-Werror,-Wimplicit-function-declaration]
                           pci_msix_free_irq(pdev, msix_map);
                           ^
drivers/vfio/pci/vfio_pci_intrs.c:511:15: error: implicit declaration of\
        function 'pci_msix_alloc_irq_at' is invalid in C99\
        [-Werror,-Wimplicit-function-declaration]
                   msix_map = pci_msix_alloc_irq_at(pdev, vector, NULL);

Provide definitions for pci_msix_alloc_irq_at() and pci_msix_free_irq() in
preparation for users that need to compile when CONFIG_PCI_MSI is
disabled.

Reported-by: kernel test robot <lkp@xxxxxxxxx>
Fixes: 34026364df8e ("PCI/MSI: Provide post-enable dynamic allocation interfaces for MSI-X")
Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/158e40e1cfcfc58ae30ecb2bbfaf86e5bba7a1ef.1675978686.git.reinette.chatre@xxxxxxxxx
---
 include/linux/pci.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index adffd65..254c8a4 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1621,6 +1621,18 @@ pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
 					      flags, NULL);
 }
 
+static inline struct msi_map pci_msix_alloc_irq_at(struct pci_dev *dev, unsigned int index,
+						   const struct irq_affinity_desc *affdesc)
+{
+	struct msi_map map = { .index = -ENOSYS, };
+
+	return map;
+}
+
+static inline void pci_msix_free_irq(struct pci_dev *pdev, struct msi_map map)
+{
+}
+
 static inline void pci_free_irq_vectors(struct pci_dev *dev)
 {
 }