linux/include/asm-cris/scatterlist.h
Jens Axboe 18dabf473e 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>
2007-10-22 21:20:01 +02:00

21 lines
498 B
C

#ifndef __ASM_CRIS_SCATTERLIST_H
#define __ASM_CRIS_SCATTERLIST_H
struct scatterlist {
char * address; /* Location data is to be transferred to */
unsigned int length;
/* The following is i386 highmem junk - not used by us */
unsigned long page_link;
unsigned int offset;/* for highmem, page offset */
};
#define sg_dma_address(sg) ((sg)->address)
#define sg_dma_len(sg) ((sg)->length)
/* i386 junk */
#define ISA_DMA_THRESHOLD (0x1fffffff)
#endif /* !(__ASM_CRIS_SCATTERLIST_H) */