Change table chaining layout

Change the page member of the scatterlist structure to be an unsigned
long, and encode more stuff in the lower bits:

- Bits 0 and 1 zero: this is a normal sg entry. Next sg entry is located
  at sg + 1.
- Bit 0 set: this is a chain entry, the next real entry is at ->page_link
  with the two low bits masked off.
- Bit 1 set: this is the final entry in the sg entry. sg_next() will return
  NULL when passed such an entry.

It's thus important that sg table users use the proper accessors to get
and set the page member.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/asm-arm/scatterlist.h b/include/asm-arm/scatterlist.h
index de2f65e..ab1d85d 100644
--- a/include/asm-arm/scatterlist.h
+++ b/include/asm-arm/scatterlist.h
@@ -5,7 +5,7 @@
 #include <asm/types.h>
 
 struct scatterlist {
-	struct page	*page;		/* buffer page			 */
+	unsigned long	page_link;
 	unsigned int	offset;		/* buffer offset		 */
 	dma_addr_t	dma_address;	/* dma address			 */
 	unsigned int	length;		/* length			 */