[PATCH 3/3] crypto: x86/aesni-intel - Add transitional selections

[Eric Biggers <ebiggers@kernel.org>]

Make CRYPTO_AES_NI_INTEL select CRYPTO_AES, CRYPTO_CBC, and CRYPTO_XTS
so that systems with CRYPTO_AES_NI_INTEL enabled are guaranteed to still
get the algorithm needed for their systems to boot with LUKS / dm-crypt.

(Later, when CRYPTO_AES_NI_INTEL is removed entirely, I plan to turn it
into a 'transitional' symbol with these selections.)

While compatibility selections haven't been used for previous migrations
of architecture-optimized code into lib/crypto/, I think it's worthwhile
in this particular case.

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 arch/x86/crypto/Kconfig | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/x86/crypto/Kconfig b/arch/x86/crypto/Kconfig
index c1842c2d7055..20f5e2a17e45 100644
--- a/arch/x86/crypto/Kconfig
+++ b/arch/x86/crypto/Kconfig
@@ -9,6 +9,9 @@ config CRYPTO_AES_NI_INTEL
 	select CRYPTO_LIB_AES
 	select CRYPTO_LIB_GF128MUL
 	select CRYPTO_SKCIPHER
+	select CRYPTO_AES
+	select CRYPTO_CBC
+	select CRYPTO_XTS
 	help
 	  AEAD cipher: AES with GCM
 
@@ -16,8 +19,13 @@ config CRYPTO_AES_NI_INTEL
 	  - AES-NI (AES new instructions)
 	  - VAES (Vector AES)
 
-	  Note: this option no longer provides the accelerated XTS, CBC, CTR,
-	  and ECB code.  For those just use CRYPTO_XTS, CRYPTO_CBC, etc.
+	  The module controlled by this option (aesni-intel.ko) no longer
+	  directly provides the accelerated ECB, CBC, CBC-CTS, CTR, XCTR, and
+	  XTS code.  Those are now provided by CRYPTO_AES (aes.ko) when the
+	  corresponding mode option (CRYPTO_XTS, CRYPTO_CBC, etc.) is enabled.
+
+	  To ensure dm-crypt continues to work in kconfigs with only this option
+	  set, this option selects CRYPTO_AES, CRYPTO_CBC, and CRYPTO_XTS.
 
 config CRYPTO_BLOWFISH_X86_64
 	tristate "Ciphers: Blowfish, modes: ECB, CBC"
-- 
2.55.0