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Donenfeld" , Ard Biesheuvel Cc: Yury Norov , linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org Subject: [PATCH v2] lib: crypto: fix comments for count_leading_zeros() Date: Thu, 12 Mar 2026 12:11:32 -0400 Message-ID: <20260312161133.249374-1-ynorov@nvidia.com> X-Mailer: git-send-email 2.43.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: BN0PR07CA0014.namprd07.prod.outlook.com (2603:10b6:408:141::7) To PH0PR12MB8800.namprd12.prod.outlook.com (2603:10b6:510:26f::12) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH0PR12MB8800:EE_|PH7PR12MB6466:EE_ X-MS-Office365-Filtering-Correlation-Id: a64bee54-0244-495e-1d57-08de805208ab X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|376014|10070799003|1800799024|18002099003|56012099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH0PR12MB8800.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(376014)(10070799003)(1800799024)(18002099003)(56012099003);DIR:OUT;SFP:1101; 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charset="utf-8" count_leading_zeros() is based on fls(), which is defined for x =3D=3D 0, contrary to ffs() family. The comment in crypto/mpi erroneously states that the function may return undef in such case. Fix the comment together with the outdated function signature, and now that COUNT_LEADING_ZEROS_0 is not referenced in the codebase, get rid of it too. Signed-off-by: Yury Norov Acked-by: Eric Biggers Reviewed-by: Andy Shevchenko --- v1: https://lore.kernel.org/all/20260310211021.95362-1-ynorov@nvidia.com/ v2: cleanup trailing whitespaces, tweak comments (Andy) include/linux/count_zeros.h | 4 +--- lib/crypto/mpi/longlong.h | 8 ++++---- 2 files changed, 5 insertions(+), 7 deletions(-) diff --git a/include/linux/count_zeros.h b/include/linux/count_zeros.h index 5b8ff5ac660d..4e5680327ece 100644 --- a/include/linux/count_zeros.h +++ b/include/linux/count_zeros.h @@ -18,7 +18,7 @@ * * If the MSB of @x is set, the result is 0. * If only the LSB of @x is set, then the result is BITS_PER_LONG-1. - * If @x is 0 then the result is COUNT_LEADING_ZEROS_0. + * If @x is 0 then the result is BITS_PER_LONG. */ static inline int count_leading_zeros(unsigned long x) { @@ -28,8 +28,6 @@ static inline int count_leading_zeros(unsigned long x) return BITS_PER_LONG - fls64(x); } =20 -#define COUNT_LEADING_ZEROS_0 BITS_PER_LONG - /** * count_trailing_zeros - Count the number of zeros from the LSB forwards * @x: The value diff --git a/lib/crypto/mpi/longlong.h b/lib/crypto/mpi/longlong.h index b6fa1d08fb55..a5ef41c8f85d 100644 --- a/lib/crypto/mpi/longlong.h +++ b/lib/crypto/mpi/longlong.h @@ -66,12 +66,12 @@ * denominator). Like udiv_qrnnd but the numbers are signed. The quotient * is rounded towards 0. * - * 5) count_leading_zeros(count, x) counts the number of zero-bits from the + * 5) count_leading_zeros(x) counts the number of zero-bits from the * msb to the first non-zero bit in the UWtype X. This is the number of - * steps X needs to be shifted left to set the msb. Undefined for X =3D= =3D 0, - * unless the symbol COUNT_LEADING_ZEROS_0 is defined to some value. + * steps X needs to be shifted left to set the msb. + * count_leading_zeros(0) =3D=3D BITS_PER_LONG * - * 6) count_trailing_zeros(count, x) like count_leading_zeros, but counts + * 6) count_trailing_zeros() like count_leading_zeros(), but counts * from the least significant end. * * 7) add_ssaaaa(high_sum, low_sum, high_addend_1, low_addend_1, --=20 2.43.0