mm: introduce io_remap_pfn_range_[prepare, complete]()

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.

Link: https://lkml.kernel.org/r/4065134[e-mail]
Signed-off-by: Lorenzo Stoakes <[e-mail]>
Reviewed-by: Jason Gunthorpe <[e-mail]>
Cc: Alexander Gordeev <[e-mail]>
Cc: Al Viro <[e-mail]>
Cc: Andreas Larsson <[e-mail]>
Cc: Andrey Konovalov <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: Baolin Wang <[e-mail]>
Cc: Baoquan He <[e-mail]>
Cc: Chatre, Reinette <[e-mail]>
Cc: Christian Borntraeger <[e-mail]>
Cc: Christian Brauner <[e-mail]>
Cc: Dan Williams <[e-mail]>
Cc: Dave Jiang <[e-mail]>
Cc: Dave Martin <[e-mail]>
Cc: Dave Young <[e-mail]>
Cc: David Hildenbrand <[e-mail]>
Cc: David S. Miller <[e-mail]>
Cc: Dmitriy Vyukov <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: Guo Ren <[e-mail]>
Cc: Heiko Carstens <[e-mail]>
Cc: Hugh Dickins <[e-mail]>
Cc: James Morse <[e-mail]>
Cc: Jan Kara <[e-mail]>
Cc: Jann Horn <[e-mail]>
Cc: Jonathan Corbet <[e-mail]>
Cc: Kevin Tian <[e-mail]>
Cc: Konstantin Komarov <[e-mail]>
Cc: Liam Howlett <[e-mail]>
Cc: "Luck, Tony" <[e-mail]>
Cc: Matthew Wilcox (Oracle) <[e-mail]>
Cc: Michal Hocko <[e-mail]>
Cc: Mike Rapoport <[e-mail]>
Cc: Muchun Song <[e-mail]>
Cc: Nicolas Pitre <[e-mail]>
Cc: Oscar Salvador <[e-mail]>
Cc: Pedro Falcato <[e-mail]>
Cc: Robin Murohy <[e-mail]>
Cc: Sumanth Korikkar <[e-mail]>
Cc: Suren Baghdasaryan <[e-mail]>
Cc: Sven Schnelle <[e-mail]>
Cc: Thomas Bogendoerfer <[e-mail]>
Cc: "Uladzislau Rezki (Sony)" <[e-mail]>
Cc: Vasily Gorbik <[e-mail]>
Cc: Vishal Verma <[e-mail]>
Cc: Vivek Goyal <[e-mail]>
Cc: Vlastimil Babka <[e-mail]>
Cc: Will Deacon <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

mm/internal.h

···
 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 = pgprot_decrypted(orig_prot);
+
+	return remap_pfn_range_complete(vma, addr, pfn, size, prot);
+}
+
 #endif	/* __MM_INTERNAL_H */