[PATCH v2 08/18] lib/bch: Replace open-coded parity calculation with parity32()

Kuan-Wei Chiu
2025-03-01T14:26:39Z

Refactor parity calculations to use the standard parity32() helper.
This change eliminates redundant implementations and improves code
efficiency.

Co-developed-by: Yu-Chun Lin <eleanor15x@gmail.com>
Signed-off-by: Yu-Chun Lin <eleanor15x@gmail.com>
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
---
lib/bch.c | 14 +-------------
1 file changed, 1 insertion(+), 13 deletions(-)

diff --git a/lib/bch.c b/lib/bch.c
index 1c0cb07cdfeb..769459749982 100644
--- a/lib/bch.c
+++ b/lib/bch.c
@@ -311,18 +311,6 @@ static inline int deg(unsigned int poly)
return fls(poly)-1;
}

-static inline int parity(unsigned int x)
-{
- /*
- * public domain code snippet, lifted from
- * http://www-graphics.stanford.edu/~seander/bithacks.html
- */
- x ^= x >> 1;
- x ^= x >> 2;
- x = (x & 0x11111111U) * 0x11111111U;
- return (x >> 28) & 1;
-}
-
/* Galois field basic operations: multiply, divide, inverse, etc. */

static inline unsigned int gf_mul(struct bch_control *bch, unsigned int a,
@@ -524,7 +512,7 @@ static int solve_linear_system(struct bch_control *bch, unsigned int *rows,
tmp = 0;
for (r = m-1; r >= 0; r--) {
mask = rows[r] & (tmp|1);
- tmp |= parity(mask) << (m-r);
+ tmp |= parity32(mask) << (m-r);
}
sol[p] = tmp >> 1;
}
--
2.34.1