From 61b6034c6cfdcb265bb453505c3d688e7567727a Mon Sep 17 00:00:00 2001 From: Slava Shwartsman Date: Thu, 29 Dec 2016 18:37:12 +0200 Subject: [PATCH] net/mlx4_en: Fix type mismatch for 32-bit systems is_power_of_2 expects unsigned long and we pass u64 max_val_cycles, this will be truncated on 32 bit systems, and the result is not what we were expecting. div_u64 expects u32 as a second argument and we pass max_val_cycles_rounded which is u64 hence it will always be truncated. Fix was tested on both 64 and 32 bit systems and got same results for max_val_cycles and max_val_cycles_rounded. Fixes: 4850cf458157 ("net/mlx4_en: Resolve dividing by zero in 32-bit system") Signed-off-by: Slava Shwartsman Signed-off-by: Tariq Toukan Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_clock.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c index 015198c14fa8..504461a464c5 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c @@ -245,13 +245,9 @@ static u32 freq_to_shift(u16 freq) { u32 freq_khz = freq * 1000; u64 max_val_cycles = freq_khz * 1000 * MLX4_EN_WRAP_AROUND_SEC; - u64 tmp_rounded = - roundup_pow_of_two(max_val_cycles) > max_val_cycles ? - roundup_pow_of_two(max_val_cycles) - 1 : UINT_MAX; - u64 max_val_cycles_rounded = is_power_of_2(max_val_cycles + 1) ? - max_val_cycles : tmp_rounded; + u64 max_val_cycles_rounded = 1ULL << fls64(max_val_cycles - 1); /* calculate max possible multiplier in order to fit in 64bit */ - u64 max_mul = div_u64(0xffffffffffffffffULL, max_val_cycles_rounded); + u64 max_mul = div64_u64(ULLONG_MAX, max_val_cycles_rounded); /* This comes from the reverse of clocksource_khz2mult */ return ilog2(div_u64(max_mul * freq_khz, 1000000)); -- 2.20.1