xip: support non-struct page backed memory

Convert XIP to support non-struct page backed memory, using VM_MIXEDMAP for
the user mappings.

This requires the get_xip_page API to be changed to an address based one.
Improve the API layering a little bit too, while we're here.

This is required in order to support XIP filesystems on memory that isn't
backed with struct page (but memory with struct page is still supported too).

Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Carsten Otte <cotte@de.ibm.com>
Cc: Jared Hulbert <jaredeh@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index bd05f5678045..2c925747bc49 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -474,8 +474,8 @@ struct address_space_operations {
         int (*releasepage) (struct page *, gfp_t);
         ssize_t (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
                         loff_t offset, unsigned long nr_segs);
-        struct page* (*get_xip_page)(struct address_space *, sector_t,
-                        int);
+        int (*get_xip_mem)(struct address_space *, pgoff_t, int,
+                                                void **, unsigned long *);
         /* migrate the contents of a page to the specified target */
         int (*migratepage) (struct address_space *,
                         struct page *, struct page *);