Introduce the request handling for dm-crypt

Now the dm-crypt code only implemented the 'based-bio' method to encrypt/ decrypt block data, which can only hanle one bio at one time. As we know, one bio must use the sequential physical address and it also has a limitation of length. Thus it may limit the big block encyrtion/decryption when some hardware support the big block data encryption.

This patch series introduc the 'based-request' method to handle the data encryption/decryption. One request can contain multiple bios, so it can handle big block data to improve the efficiency.

Also this patch refers to the Dinesh K Garg <[email protected]> and franciscofranco <[email protected]> submission of 'Request based dm-crypt', and the original link is:
https://github.com/major91/Zeta-Chromium-N5/commit/621d4821da04cfde383329ebdf4ce8711ec3329c

Now it can encrypt/decrypt successfully with read/write testing, and it shows some efficiency improvements with hardware acceleration. But I really hope to need more comments about the structure and conception. Thanks for your review.

Baolin Wang (2):
block: Introduce BIO_ENDIO_FREE for bio flags
md: dm-crypt: Introduce the request handling for dm-crypt

 block/blk-core.c              |    6 +-
 drivers/md/Kconfig            |    6 +
 drivers/md/dm-crypt.c         |  831 ++++++++++++++++++++++++++++++++++++++++-
 drivers/md/dm.c               |   13 +-
 include/linux/blk_types.h     |    6 +
 include/linux/device-mapper.h |    5 +
 6 files changed, 861 insertions(+), 6 deletions(-)

1.7.9.5