[PATCH] PCI/MSI: stub pci_write_msi_msg when CONFIG_PCI_MSI is disabled

[Luis Henriques]

Stubbing function pci_write_msi_msg when CONFIG_PCI_MSI is disabled fixes
a link failure in vfio:

drivers/built-in.o: In function `vfio_msi_set_vector_signal':
:(.text+0x626640): undefined reference to `pci_write_msi_msg'

Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 include/linux/msi.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/msi.h b/include/linux/msi.h
index a2a0068a8387..09dc375d11d8 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -105,18 +105,19 @@ struct msi_desc {
 
 struct pci_dev *msi_desc_to_pci_dev(struct msi_desc *desc);
 void *msi_desc_to_pci_sysdata(struct msi_desc *desc);
+void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg);
 #else /* CONFIG_PCI_MSI */
 static inline void *msi_desc_to_pci_sysdata(struct msi_desc *desc)
 {
 	return NULL;
 }
+static inline void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg) { }
 #endif /* CONFIG_PCI_MSI */
 
 struct msi_desc *alloc_msi_entry(struct device *dev);
 void free_msi_entry(struct msi_desc *entry);
 void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
 void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
-void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg);
 
 u32 __pci_msix_desc_mask_irq(struct msi_desc *desc, u32 flag);
 u32 __pci_msi_desc_mask_irq(struct msi_desc *desc, u32 mask, u32 flag);