[PATCHv2 0/2] dm-crypt: support relaxed memory alignment

[Keith Busch <kbusch@meta.com>]

From: Keith Busch <kbusch@kernel.org>

Direct-io can support any memory alignment the hardware allows. Device
mappers don't need to impose any software constraints on memory
alignment, so this series removes one of those limitations.

Changes from the v1, which was an incomplete RFC:

 * A block layer prep patch to allow stacking drivers to define their
   own lower dma alignment limit.

 * Prevent reporting the relaxed alignment for any of the initialization
   vector types that use the scatterlist for other purposes beyond
   encrypt/decrypt.

 * Keep the error handling for data that unaligned data, but instead
   using the block device's queue limits.

 * Use the same scatterlist setup for both the in and out vectors.

 * Use multipage bvecs.

 * Check the alignment as the scatterlist is being built.

 * A follow up patch provides support for dynamic scatterlist allocation
   when the base bio has a lot fragmented segments. 

Keith Busch (3):
  block: remove stacking default dma_alignment
  dm-crypt: allow unaligned bio_vecs for direct io
  dm-crypt: dynamic scatterlist for many segments

 block/blk-settings.c  |   1 -
 drivers/md/dm-crypt.c | 105 ++++++++++++++++++++++++++++++++++--------
 2 files changed, 86 insertions(+), 20 deletions(-)

-- 
2.47.3