From nobody Fri Dec 19 20:04:20 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5859C21C184; Sun, 24 Mar 2024 23:10:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711321838; cv=none; b=GcOa2gDNN11nrdKcK3xrBz+x7Tmyp2Ej0diZLRy8Bh4LBPi3aXoccFybHFBMHD7y6/b2G5CmqIbE2uSpSU+GwXih9HY/JkEP2twS1p9z6nLaMbPpYu11G35IOYhllg3jOZ7vA9avF6ykdC4DAnL9Jy1eRJ4kHxPHrKqTUozb9xA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711321838; c=relaxed/simple; bh=pRFSzQtLhCFk2XS/KpLm33y704/cqDGYsr0aJwn7PQY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=g7rFoM5mQE5DKJ3rMorJ2KtBKOpGcd5UwDZ9V1Rgr0KOYxXjBRzsnpXQnBAKpHmWBpH+tK24ZFk6nuS8l5J1nqJ4KG7yMea2tRsIFE/xC70xZrD6jFX1U5EnIqGmlbDWkbMd491DNsbzvDpkEYojD+X0NB3TCr90DuP7tZoH/jE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kkDBeZRB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kkDBeZRB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7F9F4C433F1; Sun, 24 Mar 2024 23:10:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1711321837; bh=pRFSzQtLhCFk2XS/KpLm33y704/cqDGYsr0aJwn7PQY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kkDBeZRB+KpL4Hf0FwYFKDHw20+Jbu5M/j/DkiFV/G3bAltRboRn8hKVGKjp07A+H LdVL51HvdtLK3weL6tAMRHjT7NSztFyZe24aUWqvAv3dSY49yoq+MNoP7JVM2E3uL2 Ys/o9xTwWMltfWxs4l53cPyu0t6HKUQVZlDxyORN68ZZrJtKSxIGH68Rtgi1wRNchx OzMN+BhgK5U9dqxiGPav5cZ6Bb72qR8BBqzVxF+5IzG9ZVbIhG4h7wJPwlWThu8ch+ e4A7GlhxWB5KuYQnIyxhUQu+D+PKLk0BUpr/96AvlmKJ333ie7lfL07F+Fw6xBatbR 111ueP7JIfkcA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Matti Vaittinen , Subhajit Ghosh , Jonathan Cameron , Sasha Levin Subject: [PATCH 6.6 566/638] iio: gts-helper: Fix division loop Date: Sun, 24 Mar 2024 19:00:03 -0400 Message-ID: <20240324230116.1348576-567-sashal@kernel.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240324230116.1348576-1-sashal@kernel.org> References: <20240324230116.1348576-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Matti Vaittinen [ Upstream commit bb76cc45dcdfcd962a5994b8fe19ab74fc6c3c3a ] The loop based 64bit division may run for a long time when dividend is a lot bigger than the divider. Replace the division loop by the div64_u64() which implementation may be significantly faster. Tested-by: Subhajit Ghosh Signed-off-by: Matti Vaittinen Fixes: 38416c28e168 ("iio: light: Add gain-time-scale helpers") Link: https://lore.kernel.org/r/Zcn-6e-0-nh2WcfU@drtxq0yyyyyyyyyyyyyby-3.re= v.dnainternet.fi Signed-off-by: Jonathan Cameron Signed-off-by: Sasha Levin --- drivers/iio/industrialio-gts-helper.c | 15 +-------------- 1 file changed, 1 insertion(+), 14 deletions(-) diff --git a/drivers/iio/industrialio-gts-helper.c b/drivers/iio/industrial= io-gts-helper.c index 7653261d2dc2b..b51eb6cb766f3 100644 --- a/drivers/iio/industrialio-gts-helper.c +++ b/drivers/iio/industrialio-gts-helper.c @@ -34,24 +34,11 @@ static int iio_gts_get_gain(const u64 max, const u64 scale) { u64 full =3D max; - int tmp =3D 1; =20 if (scale > full || !scale) return -EINVAL; =20 - if (U64_MAX - full < scale) { - /* Risk of overflow */ - if (full - scale < scale) - return 1; - - full -=3D scale; - tmp++; - } - - while (full > scale * (u64)tmp) - tmp++; - - return tmp; + return div64_u64(full, scale); } =20 /** --=20 2.43.0