linux-kernel - Re: [PATCH v2] Drivers: hv: vmbus: Ignore CHANNELMSG_TL_CONNECT

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Message-ID: <20200125214212.GL1706@sasha-vm>
Date:   Sat, 25 Jan 2020 16:42:12 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     Michael Kelley <mikelley@...rosoft.com>
Cc:     Dexuan Cui <decui@...rosoft.com>,
        KY Srinivasan <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Sasha Levin <Alexander.Levin@...rosoft.com>,
        Sunil Muthuswamy <sunilmut@...rosoft.com>,
        Andrea Parri <Andrea.Parri@...rosoft.com>,
        Wei Hu <weh@...rosoft.com>
Subject: Re: [PATCH v2] Drivers: hv: vmbus: Ignore
 CHANNELMSG_TL_CONNECT_RESULT(23)

On Mon, Jan 20, 2020 at 12:51:51AM +0000, Michael Kelley wrote:
>From: Dexuan Cui <decui@...rosoft.com> Sent: Sunday, January 19, 2020 3:29 PM
>>
>> When a Linux hv_sock app tries to connect to a Service GUID on which no
>> host app is listening, a recent host (RS3+) sends a
>> CHANNELMSG_TL_CONNECT_RESULT (23) message to Linux and this triggers such
>> a warning:
>>
>> unknown msgtype=23
>> WARNING: CPU: 2 PID: 0 at drivers/hv/vmbus_drv.c:1031 vmbus_on_msg_dpc
>>
>> Actually Linux can safely ignore the message because the Linux app's
>> connect() will time out in 2 seconds: see VSOCK_DEFAULT_CONNECT_TIMEOUT
>> and vsock_stream_connect(). We don't bother to make use of the message
>> because: 1) it's only supported on recent hosts; 2) a non-trivial effort
>> is required to use the message in Linux, but the benefit is small.
>>
>> So, let's not see the warning by silently ignoring the message.
>>
>> Signed-off-by: Dexuan Cui <decui@...rosoft.com>
>> ---
>>
>> In v2 (followed Michael Kelley's suggestions):
>>     Removed the redundant code in vmbus_onmessage()
>>     Added the new enries into channel_message_table[].
>>
>>  drivers/hv/channel_mgmt.c | 21 +++++++--------------
>>  drivers/hv/vmbus_drv.c    |  4 ++++
>>  include/linux/hyperv.h    |  2 ++
>>  3 files changed, 13 insertions(+), 14 deletions(-)
>>
>
>Reviewed-by: Michael Kelley <mikelley@...rosoft.com>

Queued up, thanks!

-- 
Thanks,
Sasha