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, 3 insertions, 2 deletions

diff --git a/arch/powerpc/sysdev/axonram.c b/arch/powerpc/sysdev/axonram.c
index d359d6e92975..7f59188cd9a1 100644
--- a/arch/powerpc/sysdev/axonram.c
+++ b/arch/powerpc/sysdev/axonram.c
@@ -143,7 +143,7 @@ axon_ram_make_request(struct request_queue *queue, struct bio *bio)
  */
 static int
 axon_ram_direct_access(struct block_device *device, sector_t sector,
-                       unsigned long *data)
+                       void **kaddr, unsigned long *pfn)
 {
         struct axon_ram_bank *bank = device->bd_disk->private_data;
         loff_t offset;
@@ -154,7 +154,8 @@ axon_ram_direct_access(struct block_device *device, sector_t sector,
                 return -ERANGE;
         }
 
-        *data = bank->ph_addr + offset;
+        *kaddr = (void *)(bank->ph_addr + offset);
+        *pfn = virt_to_phys(kaddr) >> PAGE_SHIFT;
 
         return 0;
 }