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>
diff --git a/include/asm-sh64/scatterlist.h b/include/asm-sh64/scatterlist.h
index 1c723f2..0afd856 100644
--- a/include/asm-sh64/scatterlist.h
+++ b/include/asm-sh64/scatterlist.h
@@ -14,7 +14,7 @@
#include <asm/types.h>
struct scatterlist {
- struct page * page; /* Location for highmem page, if any */
+ unsigned long page_link;
unsigned int offset;/* for highmem, page offset */
dma_addr_t dma_address;
unsigned int length;