fscrypt / f2fs: prepare I/O path for fs-verity

Hello,

These two patches restructure f2fs's read path to allow the data to go through multiple postprocessing steps, rather than just decryption as is implemented currently. This is mainly in preparation for doing authenticity verification of data via fs-verity, though this change might also be useful for other future f2fs features, e.g. compression.

These patches don't yet add the fs-verity work, however, as it depends on the rest of the fs-verity patchset. I'm planning to send the full patchset out as an RFC, but some parts need further investigation first. (The work-in-progress version can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/mhalcrow/linux.git,
branch "fs-verity-dev".)

Changed since v1:

- Define NUM_PREALLOC_POST_READ_CTXS

Eric Biggers (2):
fscrypt: allow synchronous bio decryption
f2fs: refactor read path to allow multiple postprocessing steps

 fs/crypto/bio.c                 |  35 ++++---
 fs/crypto/crypto.c              |   8 +-
 fs/crypto/fscrypt_private.h     |   1 -
 fs/ext4/readpage.c              |   2 +-
 fs/f2fs/data.c                  | 166 ++++++++++++++++++++++++--------
 fs/f2fs/f2fs.h                  |  12 ++-
 fs/f2fs/file.c                  |   4 +-
 fs/f2fs/gc.c                    |   6 +-
 fs/f2fs/inline.c                |   2 +-
 fs/f2fs/super.c                 |   6 ++
 include/linux/fscrypt_notsupp.h |  13 ++-
 include/linux/fscrypt_supp.h    |   5 +-
 12 files changed, 191 insertions(+), 69 deletions(-)

2.17.0.484.g0c8726318c-goog