CHROMIUM: verity: do all hashing in dm-bht.c

CHROMIUM: verity: do all hashing in dm-bht.c

We were doing the hashing of the disk blocks in dm-verity.c and hashing
hash blocks in dm-bht.c. We can simplifiy the code by doing all the
hashing in dm-bht.c. We couldn't do this earlier because we had
to handle unaligned reads (no longer an issue).

I also removed the BUG_ON in dm_bht_get_node because I wanted to use it
in dm_bht_check_block with depth == bht->depth.

BUG=9752
TEST=Ran dm-verity.git unit tests. Ran platform_DMVerityCorruption on H/W.

Note: Had to modify the tests to use the new interface.

Signed-off-by: Mandeep Singh Baines <msb@chromium.org>;
Change-Id: I246a39b83a727743b49fcb420e57629d69af5dfd

Committed: http://chrome-svn/viewvc/chromeos?view=rev&revision=ddd06a2

[Paul T, 2011-03-08 20:44:14]

LGTM

[Will Drewry, 2011-03-08 20:53:59]

Pending updating the comments on the changed function to reflect the new
arguments, LGTM.  (Other comment is just a non-blocking naming nit. :)

http://codereview.chromium.org/6626037/diff/1/drivers/md/dm-bht.c
File drivers/md/dm-bht.c (right):

http://codereview.chromium.org/6626037/diff/1/drivers/md/dm-bht.c#newcode590
drivers/md/dm-bht.c:590: const void *buf, int *entry_state)
nit: might prefer something more meaningful like "block" instead of just "buf".

http://codereview.chromium.org/6626037/diff/1/drivers/md/dm-bht.c#newcode1063
drivers/md/dm-bht.c:1063: const void *buf)
Please update the comments.