| Message ID | ZbJvoM3NJd_Uh_s6@drtxq0yyyyyyyyyyyyybt-3.rev.dnainternet.fi (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2] iio: gts-helper: Fix division loop | expand |
diff --git a/drivers/iio/industrialio-gts-helper.c b/drivers/iio/industrialio-gts-helper.c index 7653261d2dc2..b51eb6cb766f 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); } /**
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. Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com> Fixes: 38416c28e168 ("iio: light: Add gain-time-scale helpers") --- This change was earlier applied and reverted as it confusingly lacked of the removal of the overflow check (which is only needed when we do looping "while (full > scale * (u64)tmp)". As this loop got removed, the check got also obsolete and leaving it to the code caused some confusion. So, I marked this as a v2, where v1 is the reverted change discussed here: https://lore.kernel.org/linux-iio/ZZZ7pJBGkTdFFqiY@dc78bmyyyyyyyyyyyyydt-3.rev.dnainternet.fi/ Revision history: v1 => v2: - Drop the obsolete overflow check - Rebased on top of the v6.8-rc1 iio: gts: loop fix fix --- drivers/iio/industrialio-gts-helper.c | 15 +-------------- 1 file changed, 1 insertion(+), 14 deletions(-) base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d