From 780acb2543eaf163169f8c6d6fe52e7f94a7b0d4 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 1 Dec 2024 17:08:29 -0800 Subject: [PATCH] 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: Ard Biesheuvel Link: https://lore.kernel.org/r/20241202010844.144356-5-ebiggers@kernel.org Signed-off-by: Eric Biggers --- crypto/crc32_generic.c | 8 ++++++-- crypto/crc32c_generic.c | 8 ++++++-- 2 files changed, 12 insertions(+), 4 deletions(-) diff --git a/crypto/crc32_generic.c b/crypto/crc32_generic.c index cc064ea8240e..783a30b27398 100644 --- a/crypto/crc32_generic.c +++ b/crypto/crc32_generic.c @@ -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); diff --git a/crypto/crc32c_generic.c b/crypto/crc32c_generic.c index 04b03d825cf4..985da981d6e2 100644 --- a/crypto/crc32c_generic.c +++ b/crypto/crc32c_generic.c @@ -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); -- 2.25.1