Normalize ppm to an unsigned magnitude before using it in the increment value scaling path.
This avoids negating INT64_MIN and also prevents subtracting 62 from the reduced log sum unless the sum is still above the overflow threshold reported by Coverity. Coverity issue: 501832 Signed-off-by: Soumyadeep Hore <[email protected]> --- v2: -Addressed Bruce's comments --- drivers/net/intel/idpf/idpf_ethdev.c | 38 ++++------------------------ 1 file changed, 5 insertions(+), 33 deletions(-) diff --git a/drivers/net/intel/idpf/idpf_ethdev.c b/drivers/net/intel/idpf/idpf_ethdev.c index 5e57a45775..23a2af6332 100644 --- a/drivers/net/intel/idpf/idpf_ethdev.c +++ b/drivers/net/intel/idpf/idpf_ethdev.c @@ -1005,42 +1005,14 @@ idpf_timesync_adjust_freq(struct rte_eth_dev *dev, int64_t ppm) struct idpf_vport *vport = dev->data->dev_private; struct idpf_adapter *adapter = vport->adapter; struct idpf_ptp *ptp = adapter->ptp; - int64_t incval, diff = 0; - bool negative = false; - uint64_t div, rem; - uint64_t divisor = 1000000ULL << 16; - int shift; + uint64_t incval; + __int128 diff; int ret; + /* ppm is scaled by 2^16 to match Linux adjfine. */ incval = ptp->base_incval; - - if (ppm < 0) { - negative = true; - ppm = -ppm; - } - - /* can incval * ppm overflow ? */ - if (rte_log2_u64(incval) + rte_log2_u64(ppm) > 62) { - rem = ppm % divisor; - div = ppm / divisor; - diff = div * incval; - ppm = rem; - - shift = rte_log2_u64(incval) + rte_log2_u64(ppm) - 62; - if (shift > 0) { - /* drop precision */ - ppm >>= shift; - divisor >>= shift; - } - } - - if (divisor) - diff = diff + incval * ppm / divisor; - - if (negative) - incval -= diff; - else - incval += diff; + diff = ((__int128)incval * ppm) / (1000000LL << 16); + incval += (int64_t)diff; ret = idpf_ptp_adj_dev_clk_fine(adapter, incval); if (ret) { -- 2.47.1
