Merge tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fsverity/linux

Pull fsverity updates from Eric Biggers:
 "A fix for an issue where CONFIG_FS_VERITY could be enabled without
  some of its dependencies, and a small documentation update"

* tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fsverity/linux:
  Revert "fsverity: relax build time dependency on CRYPTO_SHA256"
  Documentation: add a usecase for FS_IOC_READ_VERITY_METADATA

Author: torvalds

Documentation/filesystems/fsverity.rst

@@ -248,11 +248,17 @@ FS_IOC_READ_VERITY_METADATA
 The FS_IOC_READ_VERITY_METADATA ioctl reads verity metadata from a
 verity file.  This ioctl is available since Linux v5.12.
 
-This ioctl allows writing a server program that takes a verity file
-and serves it to a client program, such that the client can do its own
-fs-verity compatible verification of the file.  This only makes sense
-if the client doesn't trust the server and if the server needs to
-provide the storage for the client.
+This ioctl is useful for cases where the verity verification should be
+performed somewhere other than the currently running kernel.
+
+One example is a server program that takes a verity file and serves it
+to a client program, such that the client can do its own fs-verity
+compatible verification of the file.  This only makes sense if the
+client doesn't trust the server and if the server needs to provide the
+storage for the client.
+
+Another example is copying verity metadata when creating filesystem
+images in userspace (such as with ``mkfs.ext4 -d``).
 
 This is a fairly specialized use case, and most fs-verity users won't
 need this ioctl.

fs/verity/Kconfig

@@ -4,13 +4,9 @@ config FS_VERITY
 	bool "FS Verity (read-only file-based authenticity protection)"
 	select CRYPTO
 	select CRYPTO_HASH_INFO
-	# SHA-256 is implied as it's intended to be the default hash algorithm.
+	# SHA-256 is selected as it's intended to be the default hash algorithm.
 	# To avoid bloat, other wanted algorithms must be selected explicitly.
-	# Note that CRYPTO_SHA256 denotes the generic C implementation, but
-	# some architectures provided optimized implementations of the same
-	# algorithm that may be used instead. In this case, CRYPTO_SHA256 may
-	# be omitted even if SHA-256 is being used.
-	imply CRYPTO_SHA256
+	select CRYPTO_SHA256
 	help
 	  This option enables fs-verity.  fs-verity is the dm-verity
 	  mechanism implemented at the file level.  On supported