Merge tag 'for-5.4/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - crypto and DM crypt advances that allow the crypto API to reclaim
   implementation details that do not belong in DM crypt. The wrapper
   template for ESSIV generation that was factored out will also be used
   by fscrypt in the future.

 - Add root hash pkcs#7 signature verification to the DM verity target.

 - Add a new "clone" DM target that allows for efficient remote
   replication of a device.

 - Enhance DM bufio's cache to be tailored to each client based on use.
   Clients that make heavy use of the cache get more of it, and those
   that use less have reduced cache usage.

 - Add a new DM_GET_TARGET_VERSION ioctl to allow userspace to query the
   version number of a DM target (even if the associated module isn't
   yet loaded).

 - Fix invalid memory access in DM zoned target.

 - Fix the max_discard_sectors limit advertised by the DM raid target;
   it was mistakenly storing the limit in bytes rather than sectors.

 - Small optimizations and cleanups in DM writecache target.

 - Various fixes and cleanups in DM core, DM raid1 and space map portion
   of DM persistent data library.

* tag 'for-5.4/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (22 commits)
  dm: introduce DM_GET_TARGET_VERSION
  dm bufio: introduce a global cache replacement
  dm bufio: remove old-style buffer cleanup
  dm bufio: introduce a global queue
  dm bufio: refactor adjust_total_allocated
  dm bufio: call adjust_total_allocated from __link_buffer and __unlink_buffer
  dm: add clone target
  dm raid: fix updating of max_discard_sectors limit
  dm writecache: skip writecache_wait for pmem mode
  dm stats: use struct_size() helper
  dm crypt: omit parsing of the encapsulated cipher
  dm crypt: switch to ESSIV crypto API template
  crypto: essiv - create wrapper template for ESSIV generation
  dm space map common: remove check for impossible sm_find_free() return value
  dm raid1: use struct_size() with kzalloc()
  dm writecache: optimize performance by sorting the blocks for writeback_all
  dm writecache: add unlikely for getting two block with same LBA
  dm writecache: remove unused member pointer in writeback_struct
  dm zoned: fix invalid memory access
  dm verity: add root hash pkcs#7 signature verification
  ...

1 files changed, 28 insertions, 0 deletions

diff --git a/crypto/Kconfig b/crypto/Kconfig
index ad86463de715..9e524044d312 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -487,6 +487,34 @@ config CRYPTO_ADIANTUM
 
 	  If unsure, say N.
 
+config CRYPTO_ESSIV
+	tristate "ESSIV support for block encryption"
+	select CRYPTO_AUTHENC
+	help
+	  Encrypted salt-sector initialization vector (ESSIV) is an IV
+	  generation method that is used in some cases by fscrypt and/or
+	  dm-crypt. It uses the hash of the block encryption key as the
+	  symmetric key for a block encryption pass applied to the input
+	  IV, making low entropy IV sources more suitable for block
+	  encryption.
+
+	  This driver implements a crypto API template that can be
+	  instantiated either as a skcipher or as a aead (depending on the
+	  type of the first template argument), and which defers encryption
+	  and decryption requests to the encapsulated cipher after applying
+	  ESSIV to the input IV. Note that in the aead case, it is assumed
+	  that the keys are presented in the same format used by the authenc
+	  template, and that the IV appears at the end of the authenticated
+	  associated data (AAD) region (which is how dm-crypt uses it.)
+
+	  Note that the use of ESSIV is not recommended for new deployments,
+	  and so this only needs to be enabled when interoperability with
+	  existing encrypted volumes of filesystems is required, or when
+	  building for a particular system that requires it (e.g., when
+	  the SoC in question has accelerated CBC but not XTS, making CBC
+	  combined with ESSIV the only feasible mode for h/w accelerated
+	  block encryption)
+
 comment "Hash modes"
 
 config CRYPTO_CMAC