[PATCH 4.19 101/247] hwrng: timeriomem - Fix cooldown period calculation

From: Greg Kroah-Hartman
Date: Mon Mar 01 2021 - 15:28:49 EST


From: Jan Henrik Weinstock <jan.weinstock@xxxxxxxxxxxxxx>

[ Upstream commit e145f5565dc48ccaf4cb50b7cfc48777bed8c100 ]

Ensure cooldown period tolerance of 1% is actually accounted for.

Fixes: ca3bff70ab32 ("hwrng: timeriomem - Improve performance...")
Signed-off-by: Jan Henrik Weinstock <jan.weinstock@xxxxxxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/char/hw_random/timeriomem-rng.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/hw_random/timeriomem-rng.c b/drivers/char/hw_random/timeriomem-rng.c
index f615684028af7..ba01f24db6db0 100644
--- a/drivers/char/hw_random/timeriomem-rng.c
+++ b/drivers/char/hw_random/timeriomem-rng.c
@@ -72,7 +72,7 @@ static int timeriomem_rng_read(struct hwrng *hwrng, void *data,
*/
if (retval > 0)
usleep_range(period_us,
- period_us + min(1, period_us / 100));
+ period_us + max(1, period_us / 100));

*(u32 *)data = readl(priv->io_base);
retval += sizeof(u32);
--
2.27.0