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From:   Salil Mehta <salil.mehta@huawei.com>
To:     <davem@davemloft.net>
CC:     <salil.mehta@huawei.com>, <yisen.zhuang@huawei.com>,
        <lipeng321@huawei.com>, <mehta.salil@opnsrc.net>,
        <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linuxarm@huawei.com>, Yunsheng Lin <linyunsheng@huawei.com>
Subject: [PATCH net-next 07/10] net: hns3: Fix warning bug when doing lp selftest
Date:   Fri, 6 Jul 2018 11:28:01 +0100
Message-ID: <20180706102804.196-8-salil.mehta@huawei.com>
In-Reply-To: <20180706102804.196-1-salil.mehta@huawei.com>
References: <20180706102804.196-1-salil.mehta@huawei.com>
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From: Yunsheng Lin <linyunsheng@huawei.com>

The napi_alloc_skb is excepted to be called under the
non-preemptible code path when it is called by hns3_clean_rx_ring
during loopback selftest, otherwise the below warning will be
logged:

[   92.420780] BUG: using smp_processor_id() in preemptible
[00000000] code: ethtool/1873
<SNIP>
[   92.463202]  check_preemption_disabled+0xf8/0x100
[   92.467893]  debug_smp_processor_id+0x1c/0x28
[   92.472239]  __napi_alloc_skb+0x30/0x130
[   92.476158]  hns3_clean_rx_ring+0x118/0x5f0 [hns3]
[   92.480941]  hns3_self_test+0x32c/0x4d0 [hns3]
[   92.485375]  ethtool_self_test+0xdc/0x1e8
[   92.489372]  dev_ethtool+0x1020/0x1da8
[   92.493109]  dev_ioctl+0x188/0x3a0
[   92.496499]  sock_do_ioctl+0xf4/0x208
[   92.500148]  sock_ioctl+0x228/0x3e8
[   92.503626]  do_vfs_ioctl+0xc4/0x880
[   92.507189]  SyS_ioctl+0x94/0xa8
[   92.510404]  el0_svc_naked+0x30/0x34

This patch fix it by disabling preemption when calling
hns3_clean_rx_ring during loopback selftest.

Fixes: c39c4d98dc65 ("net: hns3: Add mac loopback selftest support in hns3 driver")
Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
---
 drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
index 40c0425..11620e0 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
@@ -201,7 +201,9 @@ static u32 hns3_lb_check_rx_ring(struct hns3_nic_priv *priv, u32 budget)
 		rx_group = &ring->tqp_vector->rx_group;
 		pre_rx_pkt = rx_group->total_packets;
 
+		preempt_disable();
 		hns3_clean_rx_ring(ring, budget, hns3_lb_check_skb_data);
+		preempt_enable();
 
 		rcv_good_pkt_total += (rx_group->total_packets - pre_rx_pkt);
 		rx_group->total_packets = pre_rx_pkt;
-- 
2.7.4