From: Matti Vaittinen Date: Mon, 12 Feb 2024 11:20:09 +0000 (+0200) Subject: iio: gts-helper: Fix division loop X-Git-Tag: v6.9-rc1~35^2~70^2~20 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bb76cc45dcdfcd962a5994b8fe19ab74fc6c3c3a;p=thirdparty%2Fkernel%2Flinux.git iio: gts-helper: Fix division loop 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.rev.dnainternet.fi Signed-off-by: Jonathan Cameron --- diff --git a/drivers/iio/industrialio-gts-helper.c b/drivers/iio/industrialio-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 = max; - int tmp = 1; if (scale > full || !scale) return -EINVAL; - if (U64_MAX - full < scale) { - /* Risk of overflow */ - if (full - scale < scale) - return 1; - - full -= scale; - tmp++; - } - - while (full > scale * (u64)tmp) - tmp++; - - return tmp; + return div64_u64(full, scale); } /**