From: Haiyang Zhang <haiyangz@microsoft.com>
To: sashal@kernel.org, linux-hyperv@vger.kernel.org, netdev@vger.kernel.org
Cc: haiyangz@microsoft.com, kys@microsoft.com,
sthemmin@microsoft.com, olaf@aepfle.de, vkuznets@redhat.com,
davem@davemloft.net, linux-kernel@vger.kernel.org
Subject: [net PATCH] hv_netvsc: Fix unwanted wakeup in netvsc_attach()
Date: Fri, 21 Feb 2020 08:32:18 -0800 [thread overview]
Message-ID: <1582302738-24352-1-git-send-email-haiyangz@microsoft.com> (raw)
When netvsc_attach() is called by operations like changing MTU, etc.,
an extra wakeup may happen while netvsc_attach() calling
rndis_filter_device_add() which sends rndis messages when queue is
stopped in netvsc_detach(). The completion message will wake up queue 0.
We can reproduce the issue by changing MTU etc., then the wake_queue
counter from "ethtool -S" will increase beyond stop_queue counter:
stop_queue: 0
wake_queue: 1
The issue causes queue wake up, and counter increment, no other ill
effects in current code. So we didn't see any network problem for now.
To fix this, initialize tx_disable to true, and set it to false when
the NIC is ready to be attached or registered.
Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic")
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
---
drivers/net/hyperv/netvsc.c | 2 +-
drivers/net/hyperv/netvsc_drv.c | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index ae3f308..1b320bc 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -99,7 +99,7 @@ static struct netvsc_device *alloc_net_device(void)
init_waitqueue_head(&net_device->wait_drain);
net_device->destroy = false;
- net_device->tx_disable = false;
+ net_device->tx_disable = true;
net_device->max_pkt = RNDIS_MAX_PKT_DEFAULT;
net_device->pkt_align = RNDIS_PKT_ALIGN_DEFAULT;
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 65e12cb..2c0a24c 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -1068,6 +1068,7 @@ static int netvsc_attach(struct net_device *ndev,
}
/* In any case device is now ready */
+ nvdev->tx_disable = false;
netif_device_attach(ndev);
/* Note: enable and attach happen when sub-channels setup */
@@ -2476,6 +2477,8 @@ static int netvsc_probe(struct hv_device *dev,
else
net->max_mtu = ETH_DATA_LEN;
+ nvdev->tx_disable = false;
+
ret = register_netdevice(net);
if (ret != 0) {
pr_err("Unable to register netdev.\n");
--
1.8.3.1
next reply other threads:[~2020-02-21 16:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-21 16:32 Haiyang Zhang [this message]
2020-02-24 0:33 ` [net PATCH] hv_netvsc: Fix unwanted wakeup in netvsc_attach() David Miller
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