return pfn from direct_access, for XIP

Alter the block device ->direct_access() API to work with the new
get_xip_mem() API (that requires both kaddr and pfn are returned).

Some architectures will not do the right thing in their virt_to_page() for use
by XIP (to translate from the kernel virtual address returned by
direct_access(), to a user mappable pfn in XIP's page fault handler.

However, we can't switch it to just return the pfn and not the kaddr, because
we have no good way to get a kva from a pfn, and XIP requires the kva for its
read(2) and write(2) handlers.  So we have to return both.

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

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index d6d7c52055c6..bd05f5678045 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1178,7 +1178,8 @@ struct block_device_operations {
         int (*ioctl) (struct inode *, struct file *, unsigned, unsigned long);
         long (*unlocked_ioctl) (struct file *, unsigned, unsigned long);
         long (*compat_ioctl) (struct file *, unsigned, unsigned long);
-        int (*direct_access) (struct block_device *, sector_t, unsigned long *);
+        int (*direct_access) (struct block_device *, sector_t,
+                                                void **, unsigned long *);
         int (*media_changed) (struct gendisk *);
         int (*revalidate_disk) (struct gendisk *);
         int (*getgeo)(struct block_device *, struct hd_geometry *);