[PATCH] PCI/MSI: Provide stubs for IMS functions

Reinette Chatre
2023-10-17T17:56:49Z

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 for use when callers
are compiled with CONFIG_PCI_MSI disabled.

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@intel.com>
Cc: stable@vger.kernel.org # v6.2+
---

This is a preparatory patch for the first caller of these
functions (VFIO) for which work is in progress:
https://lore.kernel.org/lkml/cover.1696609476.git.reinette.chatre@intel.com/

checkpatch.pl complains about the usage of ENOSYS but
it does appear to be the custom.

include/linux/pci.h | 34 ++++++++++++++++++++++++++--------
1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8c7c2c3c6c65..b56417276042 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 +1726,25 @@ 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 +2642,6 @@ 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