Merge tag 'crc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux

Pull CRC updates from Eric Biggers:

- Reorganize the architecture-optimized CRC32 and CRC-T10DIF code to b

Merge tag 'crc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux

Pull CRC updates from Eric Biggers:

- Reorganize the architecture-optimized CRC32 and CRC-T10DIF code to be
directly accessible via the library API, instead of requiring the
crypto API. This is much simpler and more efficient.

- Convert some users such as ext4 to use the CRC32 library API instead
of the crypto API. More conversions like this will come later.

- Add a KUnit test that tests and benchmarks multiple CRC variants.
Remove older, less-comprehensive tests that are made redundant by
this.

- Add an entry to MAINTAINERS for the kernel's CRC library code. I'm
volunteering to maintain it. I have additional cleanups and
optimizations planned for future cycles.

* tag 'crc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux: (31 commits)
MAINTAINERS: add entry for CRC library
powerpc/crc: delete obsolete crc-vpmsum_test.c
lib/crc32test: delete obsolete crc32test.c
lib/crc16_kunit: delete obsolete crc16_kunit.c
lib/crc_kunit.c: add KUnit test suite for CRC library functions
powerpc/crc-t10dif: expose CRC-T10DIF function through lib
arm64/crc-t10dif: expose CRC-T10DIF function through lib
arm/crc-t10dif: expose CRC-T10DIF function through lib
x86/crc-t10dif: expose CRC-T10DIF function through lib
crypto: crct10dif - expose arch-optimized lib function
lib/crc-t10dif: add support for arch overrides
lib/crc-t10dif: stop wrapping the crypto API
scsi: target: iscsi: switch to using the crc32c library
f2fs: switch to using the crc32 library
jbd2: switch to using the crc32c library
ext4: switch to using the crc32c library
lib/crc32: make crc32c() go directly to lib
bcachefs: Explicitly select CRYPTO from BCACHEFS_FS
x86/crc32: expose CRC32 functions through lib
x86/crc32: update prototype for crc32_pclmul_le_16()
...

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lib/crc32: expose whether the lib is really optimized at runtime

Make the CRC32 library export a function crc32_optimizations() which
returns flags that indicate which CRC32 functions are actually e

lib/crc32: expose whether the lib is really optimized at runtime

Make the CRC32 library export a function crc32_optimizations() which
returns flags that indicate which CRC32 functions are actually executing
optimized code at runtime.

This will be used to determine whether the crc32[c]-$arch shash
algorithms should be registered in the crypto API. btrfs could also
start using these flags instead of the hack that it currently uses where
it parses the crypto_shash_driver_name.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20241202010844.144356-4-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

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lib/crc32: improve support for arch-specific overrides

Currently the CRC32 library functions are defined as weak symbols, and
the arm64 and riscv architectures override them.

This method of arch-sp

lib/crc32: improve support for arch-specific overrides

Currently the CRC32 library functions are defined as weak symbols, and
the arm64 and riscv architectures override them.

This method of arch-specific overrides has the limitation that it only
works when both the base and arch code is built-in. Also, it makes the
arch-specific code be silently not used if it is accidentally built with
lib-y instead of obj-y; unfortunately the RISC-V code does this.

This commit reorganizes the code to have explicit *_arch() functions
that are called when they are enabled, similar to how some of the crypto
library code works (e.g. chacha_crypt() calls chacha_crypt_arch()).

Make the existing kconfig choice for the CRC32 implementation also
control whether the arch-optimized implementation (if one is available)
is enabled or not. Make it enabled by default if CRC32 is also enabled.

The result is that arch-optimized CRC32 library functions will be
included automatically when appropriate, but it is now possible to
disable them. They can also now be built as a loadable module if the
CRC32 library functions happen to be used only by loadable modules, in
which case the arch and base CRC32 modules will be automatically loaded
via direct symbol dependency when appropriate.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20241202010844.144356-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@google.com>

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