tree f6ce2fd3c7e3f9c2c7b4fbd9946199572bd9f622
parent 58b053e4ce9d2fc3023645c1b96e537c72aa8d9a
author Jens Axboe <jens.axboe@oracle.com> 1193075840 +0200
committer Jens Axboe <jens.axboe@oracle.com> 1193080801 +0200

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>