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>

include/asm-alpha/scatterlist.h

@@ -5,7 +5,7 @@
 #include <asm/types.h>
   
 struct scatterlist {
-	struct page *page;
+	unsigned long page_link;
 	unsigned int offset;
 
 	unsigned int length;

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			 */

include/asm-avr32/scatterlist.h

@@ -4,7 +4,7 @@
 #include <asm/types.h>
 
 struct scatterlist {
-    struct page		*page;
+    unsigned long	page_link;
     unsigned int	offset;
     dma_addr_t		dma_address;
     unsigned int	length;

include/asm-blackfin/scatterlist.h

@@ -4,7 +4,7 @@
 #include <linux/mm.h>
 
 struct scatterlist {
-	struct page *page;
+	unsigned long page_link;
 	unsigned int offset;
 	dma_addr_t dma_address;
 	unsigned int length;

include/asm-cris/scatterlist.h

@@ -6,7 +6,7 @@ struct scatterlist {
 	unsigned int length;
 
 	/* The following is i386 highmem junk - not used by us */
-	struct page * page; /* Location for highmem page, if any */
+	unsigned long page_link;
 	unsigned int offset;/* for highmem, page offset */
 
 };

include/asm-frv/scatterlist.h

@@ -22,7 +22,7 @@
  * and that's it. There's no excuse for not highmem enabling YOUR driver. /jens
  */
 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;

include/asm-h8300/scatterlist.h

@@ -4,7 +4,7 @@
 #include <asm/types.h>
 
 struct scatterlist {
-	struct page	*page;
+	unsigned long	page_link;
 	unsigned int	offset;
 	dma_addr_t	dma_address;
 	unsigned int	length;

include/asm-ia64/scatterlist.h

@@ -9,7 +9,7 @@
 #include <asm/types.h>
 
 struct scatterlist {
-	struct page *page;
+	unsigned long page_link;
 	unsigned int offset;
 	unsigned int length;	/* buffer length */
 

include/asm-m32r/scatterlist.h

@@ -6,7 +6,7 @@
 struct scatterlist {
     char *  address;    /* Location data is to be transferred to, NULL for
                          * highmem page */
-    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;

include/asm-m68k/scatterlist.h

@@ -4,7 +4,7 @@
 #include <linux/types.h>
 
 struct scatterlist {
-	struct page *page;
+	unsigned long page_link;
 	unsigned int offset;
 	unsigned int length;
 

include/asm-m68knommu/scatterlist.h

@@ -5,7 +5,7 @@
 #include <asm/types.h>
 
 struct scatterlist {
-	struct page	*page;
+	unsigned long	page_link;
 	unsigned int	offset;
 	dma_addr_t	dma_address;
 	unsigned int	length;

include/asm-mips/scatterlist.h

@@ -4,7 +4,7 @@
 #include <asm/types.h>
 
 struct scatterlist {
-	struct page *	page;
+	unsigned long	page_link;
 	unsigned int	offset;
 	dma_addr_t	dma_address;
 	unsigned int	length;

include/asm-parisc/scatterlist.h

@@ -5,7 +5,7 @@
 #include <asm/types.h>
 
 struct scatterlist {
-	struct page *page;
+	unsigned long page_link;
 	unsigned int offset;
 
 	unsigned int length;

include/asm-powerpc/scatterlist.h

@@ -14,7 +14,7 @@
 #include <asm/dma.h>
 
 struct scatterlist {
-	struct page *page;
+	unsigned long page_link;
 	unsigned int offset;
 	unsigned int length;
 

include/asm-s390/scatterlist.h

@@ -2,7 +2,7 @@
 #define _ASMS390_SCATTERLIST_H
 
 struct scatterlist {
-    struct page *page;
+    unsigned long page_link;
     unsigned int offset;
     unsigned int length;
 };

include/asm-sh/scatterlist.h

@@ -4,7 +4,7 @@
 #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;

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;

include/asm-sparc/scatterlist.h

@@ -5,7 +5,7 @@
 #include <linux/types.h>
 
 struct scatterlist {
-	struct page *page;
+	unsigned long page_link;
 	unsigned int offset;
 
 	unsigned int length;

include/asm-sparc64/scatterlist.h

@@ -6,7 +6,7 @@
 #include <asm/types.h>
 
 struct scatterlist {
-	struct page	*page;
+	unsigned long	page_link;
 	unsigned int	offset;
 
 	unsigned int	length;

include/asm-v850/scatterlist.h

@@ -17,7 +17,7 @@
 #include <asm/types.h>
 
 struct scatterlist {
-	struct page	*page;
+	unsigned long	page_link;
 	unsigned	offset;
 	dma_addr_t	dma_address;
 	unsigned	length;