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Drivers: hv: vmbus: Ignore CHANNELMSG_TL_CONNECT_RESULT(23) 

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@microsoft.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Dexuan Cui 2020-01-19 15:29:22 -08:00 committed by Sasha Levin
parent 382a462217
commit ddc9d357b9
3 changed files with 13 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/hv/channel_mgmt.c
View File

@ -1351,6 +1351,8 @@ channel_message_table[CHANNELMSG_COUNT] = {
{ CHANNELMSG_19, 0, NULL },
{ CHANNELMSG_20, 0, NULL },
{ CHANNELMSG_TL_CONNECT_REQUEST, 0, NULL },
{ CHANNELMSG_22, 0, NULL },
{ CHANNELMSG_TL_CONNECT_RESULT, 0, NULL },
};
/*
@ -1362,25 +1364,16 @@ void vmbus_onmessage(void *context)
{
struct hv_message *msg = context;
struct vmbus_channel_message_header *hdr;
int size;
hdr = (struct vmbus_channel_message_header *)msg->u.payload;
size = msg->header.payload_size;
trace_vmbus_on_message(hdr);
if (hdr->msgtype >= CHANNELMSG_COUNT) {
pr_err("Received invalid channel message type %d size %d\n",
hdr->msgtype, size);
print_hex_dump_bytes("", DUMP_PREFIX_NONE,
(unsigned char *)msg->u.payload, size);
return;
}
if (channel_message_table[hdr->msgtype].message_handler)
channel_message_table[hdr->msgtype].message_handler(hdr);
else
pr_err("Unhandled channel message type %d\n", hdr->msgtype);
/*
* vmbus_on_msg_dpc() makes sure the hdr->msgtype here can not go
* out of bound and the message_handler pointer can not be NULL.
*/
channel_message_table[hdr->msgtype].message_handler(hdr);
}
/*

4
drivers/hv/vmbus_drv.c
View File

@ -1033,6 +1033,10 @@ void vmbus_on_msg_dpc(unsigned long data)
}
entry = &channel_message_table[hdr->msgtype];
if (!entry->message_handler)
goto msg_handled;
if (entry->handler_type == VMHT_BLOCKING) {
ctx = kmalloc(sizeof(*ctx), GFP_ATOMIC);
if (ctx == NULL)

2
include/linux/hyperv.h
View File

@ -425,6 +425,8 @@ enum vmbus_channel_message_type {
CHANNELMSG_19 = 19,
CHANNELMSG_20 = 20,
CHANNELMSG_TL_CONNECT_REQUEST = 21,
CHANNELMSG_22 = 22,
CHANNELMSG_TL_CONNECT_RESULT = 23,
CHANNELMSG_COUNT
};