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>

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 8eb167540b4f66e658e7977858635f6dc8139700..0370364169c4ec2ebc09218395f41615b9f49cd5 100644 (file)
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -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);
 }
 
 /*

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 4ef5a66df68095f98d32308aa87a8bc454f30d56..029378c27421d1b30a168dbe25c1ba13c4c8de57 100644 (file)
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -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)

diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 26f3aeeae1cab6cd434e34dac9fc161e91566932..41c58011431e88ead4847ba99bc06147d3ecf290 100644 (file)
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -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
 };