hv: do not lose pending heartbeat vmbus packets

commit 407a3aee6ee2d2cb46d9ba3fc380bc29f35d020c upstream.

The host keeps sending heartbeat packets independent of the
guest responding to them.  Even though we respond to the heartbeat messages at
interrupt level, we can have situations where there maybe multiple heartbeat
messages pending that have not been responded to. For instance this occurs when the
VM is paused and the host continues to send the heartbeat messages.
Address this issue by draining and responding to all
the heartbeat messages that maybe pending.

Signed-off-by: Long Li <longli@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 64c778f7756f8fce2554ef552788ae926993ca51..5f69c839d72745e1a968299195490c280d073dcd 100644 (file)
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -244,10 +244,14 @@ static void heartbeat_onchannelcallback(void *context)
        struct heartbeat_msg_data *heartbeat_msg;
        u8 *hbeat_txf_buf = util_heartbeat.recv_buffer;
 
-       vmbus_recvpacket(channel, hbeat_txf_buf,
-                        PAGE_SIZE, &recvlen, &requestid);
+       while (1) {
+
+               vmbus_recvpacket(channel, hbeat_txf_buf,
+                                PAGE_SIZE, &recvlen, &requestid);
+
+               if (!recvlen)
+                       break;
 
-       if (recvlen > 0) {
                icmsghdrp = (struct icmsg_hdr *)&hbeat_txf_buf[
                                sizeof(struct vmbuspipe_hdr)];