From: Thierry Reding <tred...@nvidia.com> With this structure always defined, drivers can be always compiled, irrespective of whether or not IOMMU_API is enabled. This helps to increase compile coverage without having to build with two separate configurations.
Unused code can still be discarded by the compiler if the IS_ENABLED() macro is properly used in an if condition, such as shown below: static const struct iommu_ops iommu_ops = { ... }; static int iommu_setup(...) { ... bus_set_iommu(..., &iommu_ops); ... } ... static int iommu_probe(...) { ... if (IS_ENABLED(CONFIG_IOMMU_API)) { err = iommu_setup(...); ... } ... } That pattern will allow the compiler to notice that setup_iommu() is never called if IOMMU_API is not selected, which will allow it to discard its code and all data referenced from it. Signed-off-by: Thierry Reding <tred...@nvidia.com> --- include/linux/iommu.h | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/include/linux/iommu.h b/include/linux/iommu.h index 20f9a527922a..0b5222c7ff97 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -83,8 +83,6 @@ enum iommu_attr { DOMAIN_ATTR_MAX, }; -#ifdef CONFIG_IOMMU_API - /** * struct iommu_ops - iommu ops and capabilities * @domain_init: init iommu domain @@ -140,6 +138,8 @@ struct iommu_ops { #define IOMMU_GROUP_NOTIFY_UNBIND_DRIVER 5 /* Pre Driver unbind */ #define IOMMU_GROUP_NOTIFY_UNBOUND_DRIVER 6 /* Post Driver unbind */ +#ifdef CONFIG_IOMMU_API + extern int bus_set_iommu(struct bus_type *bus, const struct iommu_ops *ops); extern bool iommu_present(struct bus_type *bus); extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus); @@ -242,9 +242,6 @@ static inline int report_iommu_fault(struct iommu_domain *domain, #else /* CONFIG_IOMMU_API */ -struct iommu_ops {}; -struct iommu_group {}; - static inline bool iommu_present(struct bus_type *bus) { return false; -- 2.0.3 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu