Nathan Chancellor [off-list ref] writes:

On Thu, Jan 30, 2020 at 05:43:56PM -0800, Randy Dunlap wrote:

quoted

On 1/30/20 3:26 PM, Nathan Chancellor wrote:

quoted

When building arm32 allmodconfig:

ERROR: "__aeabi_uldivmod"
[drivers/net/ethernet/mellanox/mlxsw/mlxsw_spectrum.ko] undefined!

rate_bytes_ps has type u64, we need to use a 64-bit division helper to
avoid a build error.

Fixes: a44f58c41bfb ("mlxsw: spectrum_qdisc: Support offloading of TBF Qdisc")
Signed-off-by: Nathan Chancellor <redacted>
---
 drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c
index 79a2801d59f6..65e681ef01e8 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_qdisc.c

@@ -614,7 +614,7 @@ mlxsw_sp_qdisc_tbf_rate_kbps(struct tc_tbf_qopt_offload_replace_params *p)
 	/* TBF interface is in bytes/s, whereas Spectrum ASIC is configured in
 	 * Kbits/s.
 	 */
-	return p->rate.rate_bytes_ps / 1000 * 8;
+	return div_u64(p->rate.rate_bytes_ps, 1000 * 8);

not quite right AFAICT.

try either
	return div_u64(p->rate.rate_bytes_ps * 8, 1000);
or
	return div_u64(p->rate.rate_bytes_ps, 1000) * 8;

Gah, I swear I can math... Thank you for catching this, v2 incoming with
the later because I think it looks better.

Yes, that's the correct choice. Divide first, that way we can't
overflow.

Thanks for taking care of this.