Commit b82f7229 authored by Eric Biggers's avatar Eric Biggers Committed by Jakub Kicinski
Browse files

lib/crc32: remove unused support for CRC32C combination 



crc32c_combine() and crc32c_shift() are no longer used (except by the
KUnit test that tests them), and their current implementation is very
slow.  Remove them.

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Link: https://patch.msgid.link/20250519175012.36581-8-ebiggers@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 70c96c7c

include/linux/crc32.h

+0 −23
Original line number Diff line number Diff line
@@ -76,29 +76,6 @@ static inline u32 crc32_le_combine(u32 crc1, u32 crc2, size_t len2) 
	return crc32_le_shift(crc1, len2) ^ crc2;

}



u32 crc32c_shift(u32 crc, size_t len);



/**

 * crc32c_combine - Combine two crc32c check values into one. For two sequences

 *		    of bytes, seq1 and seq2 with lengths len1 and len2, crc32c()

 *		    check values were calculated for each, crc1 and crc2.

 *

 * @crc1: crc32c of the first block

 * @crc2: crc32c of the second block

 * @len2: length of the second block

 *

 * Return: The crc32c() check value of seq1 and seq2 concatenated, requiring

 *	   only crc1, crc2, and len2. Note: If seq_full denotes the concatenated

 *	   memory area of seq1 with seq2, and crc_full the crc32c() value of

 *	   seq_full, then crc_full == crc32c_combine(crc1, crc2, len2) when

 *	   crc_full was seeded with the same initializer as crc1, and crc2 seed

 *	   was 0. See also crc_combine_test().

 */

static inline u32 crc32c_combine(u32 crc1, u32 crc2, size_t len2)

{

	return crc32c_shift(crc1, len2) ^ crc2;

}



#define crc32(seed, data, length)  crc32_le(seed, (unsigned char const *)(data), length)



/*

lib/crc32.c

+0 −6
Original line number Diff line number Diff line
@@ -119,12 +119,6 @@ u32 crc32_le_shift(u32 crc, size_t len) 
}

EXPORT_SYMBOL(crc32_le_shift);



u32 crc32c_shift(u32 crc, size_t len)

{

	return crc32_generic_shift(crc, len, CRC32C_POLY_LE);

}

EXPORT_SYMBOL(crc32c_shift);



u32 crc32_be_base(u32 crc, const u8 *p, size_t len)

{

	while (len--)

lib/tests/crc_kunit.c

+0 −6
Original line number Diff line number Diff line
@@ -391,17 +391,11 @@ static u64 crc32c_wrapper(u64 crc, const u8 *p, size_t len) 
	return crc32c(crc, p, len);

}



static u64 crc32c_combine_wrapper(u64 crc1, u64 crc2, size_t len2)

{

	return crc32c_combine(crc1, crc2, len2);

}



static const struct crc_variant crc_variant_crc32c = {

	.bits = 32,

	.le = true,

	.poly = 0x82f63b78,

	.func = crc32c_wrapper,

	.combine_func = crc32c_combine_wrapper,

};



static void crc32c_test(struct kunit *test)