Merge remote-tracking branch 'aosp/upstream-f2fs-stable-linux-4.14.y' into android-4.14

* aosp/upstream-f2fs-stable-linux-4.14.y:
  fs-verity: use u64_to_user_ptr()
  fs-verity: use mempool for hash requests
  fs-verity: implement readahead of Merkle tree pages
  ext4: readpages() should submit IO as read-ahead
  fs-verity: implement readahead for FS_IOC_ENABLE_VERITY
  fscrypt: improve format of no-key names
  ubifs: allow both hash and disk name to be provided in no-key names
  ubifs: don't trigger assertion on invalid no-key filename
  fscrypt: clarify what is meant by a per-file key
  fscrypt: derive dirhash key for casefolded directories
  fscrypt: don't allow v1 policies with casefolding
  fscrypt: add "fscrypt_" prefix to fname_encrypt()
  fscrypt: don't print name of busy file when removing key
  fscrypt: document gfp_flags for bounce page allocation
  fscrypt: optimize fscrypt_zeroout_range()
  fscrypt: remove redundant bi_status check
  fscrypt: Allow modular crypto algorithms
  fscrypt: include <linux/ioctl.h> in UAPI header
  fscrypt: don't check for ENOKEY from fscrypt_get_encryption_info()
  fscrypt: remove fscrypt_is_direct_key_policy()
  fscrypt: move fscrypt_valid_enc_modes() to policy.c
  fscrypt: check for appropriate use of DIRECT_KEY flag earlier
  fscrypt: split up fscrypt_supported_policy() by policy version
  fscrypt: introduce fscrypt_needs_contents_encryption()
  fscrypt: move fscrypt_d_revalidate() to fname.c
  fscrypt: constify inode parameter to filename encryption functions
  fscrypt: constify struct fscrypt_hkdf parameter to fscrypt_hkdf_expand()
  fscrypt: verify that the crypto_skcipher has the correct ivsize
  fscrypt: use crypto_skcipher_driver_name()
  fscrypt: support passing a keyring key to FS_IOC_ADD_ENCRYPTION_KEY
  keys: Export lookup_user_key to external users
  f2fs: fix build error on PAGE_KERNEL_RO

Conflicts:
        fs/crypto/Kconfig
        fs/crypto/bio.c
        fs/crypto/fname.c
        fs/crypto/fscrypt_private.h
        fs/crypto/keyring.c
        fs/crypto/keysetup.c
        fs/ubifs/dir.c
        include/uapi/linux/fscrypt.h

Resolved the conflicts as per the corresponding android-mainline change,
Ib1e6b9eda8fb5dcfc6bdc8fa89d93f72b088c5f6.

Bug: 148667616
Change-Id: I5f8b846f0cd4d5403d8c61b9e12acb4581fac6f7
Signed-off-by: Eric Biggers <ebiggers@google.com>