linux-kernel - [PATCH v2] mlxsw: spectrum_qdisc: Fix 64-bit division error in mlxsw_sp_qdisc_tbf_rate

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Message-Id: <20200131015123.55400-1-natechancellor@gmail.com>
Date:   Thu, 30 Jan 2020 18:51:23 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Jiri Pirko <jiri@...lanox.com>, Ido Schimmel <idosch@...lanox.com>,
        "David S. Miller" <davem@...emloft.net>
Cc:     Petr Machata <petrm@...lanox.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org, Randy Dunlap <rdunlap@...radead.org>,
        Nathan Chancellor <natechancellor@...il.com>
Subject: [PATCH v2] mlxsw: spectrum_qdisc: Fix 64-bit division error in mlxsw_sp_qdisc_tbf_rate_kbps

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 <natechancellor@...il.com>
---

v1 -> v2:

* Fix incorrect math as pointed out by Randy Dunlap

 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..02526c53d4f5 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;
 }
 
 static int
-- 
2.25.0