[RFC PATCH V2 01/18] PCI/MSI: Provide stubs for IMS functions

[Reinette Chatre]

The IMS related functions (pci_create_ims_domain(),
pci_ims_alloc_irq(), and pci_ims_free_irq()) are not declared
when CONFIG_PCI_MSI is disabled.

Provide definitions of these functions that can be used
when callers need to compile when CONFIG_PCI_MSI is disabled.

This is a preparatory patch for the first caller of these
functions (VFIO).

Fixes: 0194425af0c8 ("PCI/MSI: Provide IMS (Interrupt Message Store) support")
Fixes: c9e5bea27383 ("PCI/MSI: Provide pci_ims_alloc/free_irq()")
Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx      # v6.2+
---
I plan to send this patch separately to PCI folks, pending the
outcome of this work.

 include/linux/pci.h | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8c7c2c3c6c65..68a52bc01864 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1624,6 +1624,8 @@ struct msix_entry {
 	u16	entry;	/* Driver uses to specify entry, OS writes */
 };
 
+struct msi_domain_template;
+
 #ifdef CONFIG_PCI_MSI
 int pci_msi_vec_count(struct pci_dev *dev);
 void pci_disable_msi(struct pci_dev *dev);
@@ -1656,6 +1658,11 @@ void pci_msix_free_irq(struct pci_dev *pdev, struct msi_map map);
 void pci_free_irq_vectors(struct pci_dev *dev);
 int pci_irq_vector(struct pci_dev *dev, unsigned int nr);
 const struct cpumask *pci_irq_get_affinity(struct pci_dev *pdev, int vec);
+bool pci_create_ims_domain(struct pci_dev *pdev, const struct msi_domain_template *template,
+			   unsigned int hwsize, void *data);
+struct msi_map pci_ims_alloc_irq(struct pci_dev *pdev, union msi_instance_cookie *icookie,
+				 const struct irq_affinity_desc *affdesc);
+void pci_ims_free_irq(struct pci_dev *pdev, struct msi_map map);
 
 #else
 static inline int pci_msi_vec_count(struct pci_dev *dev) { return -ENOSYS; }
@@ -1719,6 +1726,22 @@ static inline const struct cpumask *pci_irq_get_affinity(struct pci_dev *pdev,
 {
 	return cpu_possible_mask;
 }
+static inline bool pci_create_ims_domain(struct pci_dev *pdev,
+					 const struct msi_domain_template *template,
+					 unsigned int hwsize, void *data)
+{ return false; }
+static inline struct msi_map pci_ims_alloc_irq(struct pci_dev *pdev,
+					       union msi_instance_cookie *icookie,
+					       const struct irq_affinity_desc *affdesc)
+{
+	struct msi_map map = { .index = -ENOSYS, };
+
+	return map;
+}
+static inline void pci_ims_free_irq(struct pci_dev *pdev, struct msi_map map)
+{
+}
+
 #endif
 
 /**
@@ -2616,14 +2639,6 @@ static inline bool pci_is_thunderbolt_attached(struct pci_dev *pdev)
 void pci_uevent_ers(struct pci_dev *pdev, enum  pci_ers_result err_type);
 #endif
 
-struct msi_domain_template;
-
-bool pci_create_ims_domain(struct pci_dev *pdev, const struct msi_domain_template *template,
-			   unsigned int hwsize, void *data);
-struct msi_map pci_ims_alloc_irq(struct pci_dev *pdev, union msi_instance_cookie *icookie,
-				 const struct irq_affinity_desc *affdesc);
-void pci_ims_free_irq(struct pci_dev *pdev, struct msi_map map);
-
 #include <linux/dma-mapping.h>
 
 #define pci_printk(level, pdev, fmt, arg...) \
-- 
2.34.1