Merge remote-tracking branch 'aosp/upstream-f2fs-stable-linux-4.19.y' into android-4.19

* aosp/upstream-f2fs-stable-linux-4.19.y:
  fscrypt: document testing with xfstests
  fscrypt: remove selection of CONFIG_CRYPTO_SHA256
  fscrypt: remove unnecessary includes of ratelimit.h
  fscrypt: don't set policy for a dead directory
  fscrypt: decrypt only the needed blocks in __fscrypt_decrypt_bio()
  fscrypt: support decrypting multiple filesystem blocks per page
  fscrypt: introduce fscrypt_decrypt_block_inplace()
  fscrypt: handle blocksize < PAGE_SIZE in fscrypt_zeroout_range()
  fscrypt: support encrypting multiple filesystem blocks per page
  fscrypt: introduce fscrypt_encrypt_block_inplace()
  fscrypt: clean up some BUG_ON()s in block encryption/decryption
  fscrypt: rename fscrypt_do_page_crypto() to fscrypt_crypt_block()
  fscrypt: remove the "write" part of struct fscrypt_ctx
  fscrypt: simplify bounce page handling

Change-Id: I49d9ee4b5cbb847a5fa0b736e0ff4a406b21bc1b
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>