We introduce the io_remap*() equivalents of remap_pfn_range_prepare() and
remap_pfn_range_complete() to allow for I/O remapping via mmap_prepare.

Make these internal to mm, as they should only be used by internal helpers.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
---
 mm/internal.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/mm/internal.h b/mm/internal.h
index c6655f76cf69..085e34f84bae 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1657,4 +1657,22 @@ void remap_pfn_range_prepare(struct vm_area_desc *desc, unsigned long pfn);
 int remap_pfn_range_complete(struct vm_area_struct *vma, unsigned long addr,
 		unsigned long pfn, unsigned long size, pgprot_t pgprot);
 
+static inline void io_remap_pfn_range_prepare(struct vm_area_desc *desc,
+		unsigned long orig_pfn, unsigned long size)
+{
+	const unsigned long pfn = io_remap_pfn_range_pfn(orig_pfn, size);
+
+	return remap_pfn_range_prepare(desc, pfn);
+}
+
+static inline int io_remap_pfn_range_complete(struct vm_area_struct *vma,
+		unsigned long addr, unsigned long orig_pfn, unsigned long size,
+		pgprot_t orig_prot)
+{
+	const unsigned long pfn = io_remap_pfn_range_pfn(orig_pfn, size);
+	const pgprot_t prot = io_remap_pfn_range_prot(orig_prot);
+
+	return remap_pfn_range_complete(vma, addr, pfn, size, prot);
+}
+
 #endif	/* __MM_INTERNAL_H */
-- 
2.51.0

Hi Andrew,

Could you also apply the below, so we propagate the fact that we don't need
io_remap_pfn_range_prot()?

Cheers, Lorenzo

----8<----
From cc311eeb5b155601e3223797000f13e07b28bc30 Mon Sep 17 00:00:00 2001
From: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Date: Thu, 18 Sep 2025 07:43:21 +0100
Subject: [PATCH] fixup io_remap_pfn_range_[prepare, complete]

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
 mm/internal.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/internal.h b/mm/internal.h
index 085e34f84bae..38607b2821d9 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1670,7 +1670,7 @@ static inline int io_remap_pfn_range_complete(struct vm_area_struct *vma,
 		pgprot_t orig_prot)
 {
 	const unsigned long pfn = io_remap_pfn_range_pfn(orig_pfn, size);
-	const pgprot_t prot = io_remap_pfn_range_prot(orig_prot);
+	const pgprot_t prot = pgprot_decrypted(orig_prot);

 	return remap_pfn_range_complete(vma, addr, pfn, size, prot);
 }
--
2.51.0