diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h
index e58ca25eddb7..cf5cd88e7289 100644
--- a/arch/arm/include/asm/io.h
+++ b/arch/arm/include/asm/io.h
@@ -459,9 +459,6 @@ extern void pci_iounmap(struct pci_dev *dev, void __iomem *addr);
 
 #include <asm-generic/io.h>
 
-struct bio_vec;
-extern bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
-				      const struct bio_vec *vec2);
 #define ARCH_BIOVEC_PHYS_MERGEABLE(vec1, vec2)				\
 	 (!xen_domain() || xen_biovec_phys_mergeable(vec1, vec2))
 
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 774e03ea1bb0..06119ee511cd 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -205,9 +205,6 @@ extern int valid_mmap_phys_addr_range(unsigned long pfn, size_t size);
 
 extern int devmem_is_allowed(unsigned long pfn);
 
-struct bio_vec;
-extern bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
-				      const struct bio_vec *vec2);
 #define ARCH_BIOVEC_PHYS_MERGEABLE(vec1, vec2)				\
 	 (!xen_domain() || xen_biovec_phys_mergeable(vec1, vec2))
 
diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index 7c6106216d9c..abdb501a551d 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -371,10 +371,6 @@ extern bool is_early_ioremap_ptep(pte_t *ptep);
 
 #ifdef CONFIG_XEN
 #include <xen/xen.h>
-struct bio_vec;
-
-extern bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
-				      const struct bio_vec *vec2);
 
 #define ARCH_BIOVEC_PHYS_MERGEABLE(vec1, vec2)				\
 	 (!xen_domain() || xen_biovec_phys_mergeable(vec1, vec2))
diff --git a/include/xen/xen.h b/include/xen/xen.h
index 1e1d9bd0bd37..d7a2678da77f 100644
--- a/include/xen/xen.h
+++ b/include/xen/xen.h
@@ -39,4 +39,8 @@ extern uint32_t xen_start_flags;
 #define xen_initial_domain()	(0)
 #endif	/* CONFIG_XEN_DOM0 */
 
+struct bio_vec;
+bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
+		const struct bio_vec *vec2);
+
 #endif	/* _XEN_XEN_H */