Commit 780acb25 authored by Eric Biggers's avatar Eric Biggers
Browse files

crypto: crc32 - don't unnecessarily register arch algorithms 



Instead of registering the crc32-$arch and crc32c-$arch algorithms if
the arch-specific code was built, only register them when that code was
built *and* is not falling back to the base implementation at runtime.

This avoids confusing users like btrfs which checks the shash driver
name to determine whether it is crc32c-generic.

(It would also make sense to change btrfs to test the crc32_optimization
flags itself, so that it doesn't have to use the weird hack of parsing
the driver name.  This change still makes sense either way though.)

Reviewed-by: default avatarArd Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20241202010844.144356-5-ebiggers@kernel.org


Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
parent b5ae12e0

crypto/crc32_generic.c

+6 −2
Original line number Diff line number Diff line
@@ -157,15 +157,19 @@ static struct shash_alg algs[] = {{ 
	.base.cra_init		= crc32_cra_init,

}};



static int num_algs;



static int __init crc32_mod_init(void)

{

	/* register the arch flavor only if it differs from the generic one */

	return crypto_register_shashes(algs, 1 + IS_ENABLED(CONFIG_CRC32_ARCH));

	num_algs = 1 + ((crc32_optimizations() & CRC32_LE_OPTIMIZATION) != 0);



	return crypto_register_shashes(algs, num_algs);

}



static void __exit crc32_mod_fini(void)

{

	crypto_unregister_shashes(algs, 1 + IS_ENABLED(CONFIG_CRC32_ARCH));

	crypto_unregister_shashes(algs, num_algs);

}



subsys_initcall(crc32_mod_init);

crypto/crc32c_generic.c

+6 −2
Original line number Diff line number Diff line
@@ -197,15 +197,19 @@ static struct shash_alg algs[] = {{ 
	.base.cra_init		= crc32c_cra_init,

}};



static int num_algs;



static int __init crc32c_mod_init(void)

{

	/* register the arch flavor only if it differs from the generic one */

	return crypto_register_shashes(algs, 1 + IS_ENABLED(CONFIG_CRC32_ARCH));

	num_algs = 1 + ((crc32_optimizations() & CRC32C_OPTIMIZATION) != 0);



	return crypto_register_shashes(algs, num_algs);

}



static void __exit crc32c_mod_fini(void)

{

	crypto_unregister_shashes(algs, 1 + IS_ENABLED(CONFIG_CRC32_ARCH));

	crypto_unregister_shashes(algs, num_algs);

}



subsys_initcall(crc32c_mod_init);