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

From: Vitaly Kuznetsov <vkuznets@redhat•com>
To: Stephen Hemminger <stephen@networkplumber•org>
Cc: Stephen Hemminger <sthemmin@microsoft•com>,
	Eric Dumazet <eric.dumazet@gmail•com>,
	netdev <netdev@vger•kernel.org>,
	Haiyang Zhang <haiyangz@microsoft•com>,
	linux-kernel@vger•kernel.org, devel@linuxdriverproject•org
Subject: Re: [PATCH net-next v2 2/2] hv_netvsc: hide warnings about uninitialized/missing rndis device
Date: Wed, 08 Nov 2017 10:36:30 +0100	[thread overview]
Message-ID: <87tvy5m7s1.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <CAOaVG17ctoE53UkBG4O1=962K4qOzAjteEeG6uiNDgCUGq4jYQ@mail.gmail.com> (Stephen Hemminger's message of "Wed, 8 Nov 2017 07:17:18 +0100")

Stephen Hemminger <stephen@networkplumber•org> writes:

> On Nov 2, 2017 19:35, "Vitaly Kuznetsov" <vkuznets@redhat•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@redhat•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@linuxdriverproject•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