[Devel] [PATCH vz10] configs: Build CONFIG_CRYPTO_CRC32C_INTEL in, not as a module

[Devel] [PATCH vz10] configs: Build CONFIG_CRYPTO_CRC32C_INTEL in, not as a module

[Konstantin Khorenko]

lib/libcrc32c.c binds a static tfm once, in libcrc32c_mod_init(), a
device_initcall that runs early at boot. With CRYPTO_CRC32C_INTEL=m the
accelerated driver has not registered yet, so the tfm binds to
crc32c-generic and keeps it: loading the module later cannot rebind it,
it just sits there unused. Every crc32c() caller then runs the software
crc32_body path instead of the CPU's CRC32 instruction, which lands on
every ext4/xfs/btrfs/nvme/dm-integrity checksum.

Building the driver in makes its initcall run before
libcrc32c_mod_init(), since arch/x86/ links before lib/ and both are
device_initcall. The tfm then binds to crc32c-intel from the first
allocation.

This does not remove the crypto shash wrapper crc32c() still goes
through; a direct arch-dispatch implementation would still be faster.

https://virtuozzo.atlassian.net/browse/VSTOR-145125

Feature: crc32c: hardware-accelerated checksum
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
---
 redhat/configs/custom-overrides/generic/CONFIG_CRYPTO_CRC32C_INTEL | 1 +
 1 file changed, 1 insertion(+)

diff --git a/redhat/configs/custom-overrides/generic/CONFIG_CRYPTO_CRC32C_INTEL b/redhat/configs/custom-overrides/generic/CONFIG_CRYPTO_CRC32C_INTEL
new file mode 100644
index 0000000000000..d4f84f727c85c
--- /dev/null
+++ b/redhat/configs/custom-overrides/generic/CONFIG_CRYPTO_CRC32C_INTEL
@@ -0,0 +1 @@
+CONFIG_CRYPTO_CRC32C_INTEL=y

---
base-commit: ef994d2c62a1d045543fe80aaf584139b22fbaf7
change-id: 20260914-temp2-fe6929d95c5d

Best regards,
--  
Konstantin Khorenko <khorenko@virtuozzo.com>

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Re: [Devel] [PATCH vz10] configs: Build CONFIG_CRYPTO_CRC32C_INTEL in, not as a module

[Konstantin Khorenko]

On Mon, 14 Sep 2026 19:51:19 +0200, Konstantin Khorenko wrote:
> configs: Build CONFIG_CRYPTO_CRC32C_INTEL in, not as a module

Applied to branch-rh10-6.12.0-211.52.1.20.x.vz10-ovz, will be released in rh10-6.12.0-211.52.1.20.4.vz10, thanks!

[1/1] configs: Build CONFIG_CRYPTO_CRC32C_INTEL in, not as a module
      https://bitbucket.org/virtuozzocore/vzkernel.vzs/commits/3f8c65349994

-- 
Konstantin Khorenko <khorenko@virtuozzo.com>

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