Re: [PATCH] macsec: fix crypto Kconfig dependency

[Herbert Xu <herbert@gondor.apana.org.au>]

Arnd Bergmann <arnd@arndb.de> wrote:
> The new MACsec driver uses the AES crypto algorithm, but can be configured
> even if CONFIG_CRYPTO is disabled, leading to a build error:
> 
> warning: (MAC80211 && MACSEC) selects CRYPTO_GCM which has unmet direct dependencies (CRYPTO)
> warning: (BT && CEPH_LIB && INET && MAC802154 && MAC80211 && BLK_DEV_RBD && MACSEC && AIRO_CS && LIBIPW && HOSTAP && USB_WUSB && RTLLIB_CRYPTO_CCMP && FS_ENCRYPTION && EXT4_ENCRYPTION && CEPH_FS && BIG_KEYS && ENCRYPTED_KEYS) selects CRYPTO_AES which has unmet direct dependencies (CRYPTO)
> crypto/built-in.o: In function `gcm_enc_copy_hash':
> aes_generic.c:(.text+0x2b8): undefined reference to `crypto_xor'
> aes_generic.c:(.text+0x2dc): undefined reference to `scatterwalk_map_and_copy'
> 
> This adds an explicit 'select CRYPTO' statement the way that other
> drivers handle it.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Fixes: c09440f7dcb3 ("macsec: introduce IEEE 802.1AE driver")

Thnis patch is bogus.  The build error is coming from the fact
that GCM is built-in but CRYPTO_ALGAPI is (presumably) only built
as a module.  The patch in question does nothing to address that
AFAICS.

In fact this strikes me as a kbuild bug because CRYPTO_GCM already
selects (indirectly) CRYPTO_ALGAPI so why is this happening at all?

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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