From: Vladimir Oltean olteanv@gmail.com
[ Upstream commit 68ce6688a5baefde30914fc07fc27292dbbe8320 ]
The speed divisor is used in a context expecting an s64, but it is evaluated using 32-bit arithmetic.
To avoid that happening, instead of multiplying by 1,000,000 in the first place, simplify the fraction and do a standard 32 bit division instead.
Fixes: f04b514c0ce2 ("taprio: Set default link speed to 10 Mbps in taprio_set_picos_per_byte") Reported-by: Gustavo A. R. Silva gustavo@embeddedor.com Suggested-by: Eric Dumazet eric.dumazet@gmail.com Signed-off-by: Vladimir Oltean olteanv@gmail.com Acked-by: Vinicius Costa Gomes vinicius.gomes@intel.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/sch_taprio.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -672,8 +672,7 @@ static void taprio_set_picos_per_byte(st speed = ecmd.base.speed;
skip: - picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8, - speed * 1000 * 1000); + picos_per_byte = (USEC_PER_SEC * 8) / speed;
atomic64_set(&q->picos_per_byte, picos_per_byte); netdev_dbg(dev, "taprio: set %s's picos_per_byte to: %lld, linkspeed: %d\n",