Patch "hv: do not lose pending heartbeat vmbus packets" has been added to the 4.4-stable tree

Patch "hv: do not lose pending heartbeat vmbus packets" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    hv: do not lose pending heartbeat vmbus packets

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     hv-do-not-lose-pending-heartbeat-vmbus-packets.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 407a3aee6ee2d2cb46d9ba3fc380bc29f35d020c Mon Sep 17 00:00:00 2001
From: Long Li <longli@microsoft.com>
Date: Wed, 5 Oct 2016 16:57:46 -0700
Subject: hv: do not lose pending heartbeat vmbus packets

From: Long Li <longli@microsoft.com>

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/hv/hv_util.c |   10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -283,10 +283,14 @@ static void heartbeat_onchannelcallback(
 	u8 *hbeat_txf_buf = util_heartbeat.recv_buffer;
 	struct icmsg_negotiate *negop = NULL;
 
-	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)];
 


Patches currently in stable-queue which might be from longli@microsoft.com are

queue-4.4/hv-do-not-lose-pending-heartbeat-vmbus-packets.patch