linux-kernel - Re: [PATCH net-next v2 2/2] hv_netvsc: hide warnings about uninitialized/missing rndis device

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Date:   Wed, 08 Nov 2017 10:36:30 +0100
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Stephen Hemminger <stephen@...workplumber.org>
Cc:     netdev <netdev@...r.kernel.org>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Eric Dumazet <eric.dumazet@...il.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        linux-kernel@...r.kernel.org, devel@...uxdriverproject.org
Subject: Re: [PATCH net-next v2 2/2] hv_netvsc: hide warnings about uninitialized/missing rndis device

Stephen Hemminger <stephen@...workplumber.org> writes:

> On Nov 2, 2017 19:35, "Vitaly Kuznetsov" <vkuznets@...hat.com> wrote:
>
>  Hyper-V hosts are known to send RNDIS messages even after we halt the
>  device in rndis_filter_halt_device(). Remove user visible messages
>  as they are not really useful.
>
>  Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
>  ---
>  drivers/net/hyperv/rndis_filter.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
>  diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
>  index 0648eebda829..8b1242b8d8ef 100644
>  --- a/drivers/net/hyperv/rndis_filter.c
>  +++ b/drivers/net/hyperv/rndis_filter.c
>  @@ -407,13 +407,13 @@ int rndis_filter_receive(struct net_device *ndev,
>
>  /* Make sure the rndis device state is initialized */
>  if (unlikely(!rndis_dev)) {
>  - netif_err(net_device_ctx, rx_err, ndev,
>  + netif_dbg(net_device_ctx, rx_err, ndev,
>  "got rndis message but no rndis device!\n");
>  return NVSP_STAT_FAIL;
>  }
>
>  if (unlikely(rndis_dev->state == RNDIS_DEV_UNINITIALIZED)) {
>  - netif_err(net_device_ctx, rx_err, ndev,
>  + netif_dbg(net_device_ctx, rx_err, ndev,
>  "got rndis message uninitialized\n");
>  return NVSP_STAT_FAIL;
>  }
>  --
>  2.13.6
>
>  _______________________________________________
>  devel mailing list
>  devel@...uxdriverproject.org
>  http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
>
> This should never happen since host removal should be setting device
> down which disables NAPI. If this is not working correctly, that needs
> to be fixed (rather than silencing the message).

This happens in between we halt RNDIS device in
rndis_filter_halt_device() and NAPI shutdown from netvsc_device_remove()
while the window is still open.

>
> Don't shoot the messenger

These messages are of no use for a random user: you change MTU on your
device and see 'got rndis message uninitialized' - what are you supposed
to do? I leave them at debugging level for us to actually debug.

-- 
  Vitaly

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