Re: [PATCH v3 04/18] crypto: crc32 - don't unnecessarily register arch algorithms
From: Ard Biesheuvel <ardb@kernel.org>
Date: 2024-11-04 10:56:58
Also in:
linux-arch, linux-arm-kernel, linux-crypto, linux-ext4, linux-f2fs-devel, linux-mips, linux-riscv, linux-s390, linux-scsi, lkml, loongarch, sparclinux
On Sun, 3 Nov 2024 at 23:32, Eric Biggers [off-list ref] wrote:
From: Eric Biggers <redacted> 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.) Signed-off-by: Eric Biggers <redacted>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
quoted hunk ↗ jump to hunk
--- 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@@ -155,19 +155,23 @@ static struct shash_alg algs[] = {{ .base.cra_ctxsize = sizeof(u32), .base.cra_module = THIS_MODULE, .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); module_exit(crc32_mod_fini);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@@ -195,19 +195,23 @@ static struct shash_alg algs[] = {{ .base.cra_ctxsize = sizeof(struct chksum_ctx), .base.cra_module = THIS_MODULE, .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); module_exit(crc32c_mod_fini); --2.47.0