Re: [PATCH v2] Drivers: hv: vmbus: Ignore CHANNELMSG_TL_CONNECT_RESULT(23)

From: Sasha Levin
Date: Sat Jan 25 2020 - 16:42:16 EST


On Mon, Jan 20, 2020 at 12:51:51AM +0000, Michael Kelley wrote:
From: Dexuan Cui <decui@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx>
---

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@xxxxxxxxxxxxx>

Queued up, thanks!

--
Thanks,
Sasha