From 38c06c29bada78c4805000bfb9b7f19cd691461b Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Sat, 11 Apr 2015 18:07:43 -0700
Subject: Drivers: hv: vss: process deferred messages when we complete the
 transaction

In theory, the host is not supposed to issue any requests before be reply to
the previous one. In KVP we, however, support the following scenarios:
1) A message was received before userspace daemon registered;
2) A message was received while the previous one is still being processed.
In VSS we support only the former. Add support for the later, use
hv_poll_channel() to do the job.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: Alex Ng <alexng@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/hv/hv_snapshot.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

(limited to 'drivers/hv')

diff --git a/drivers/hv/hv_snapshot.c b/drivers/hv/hv_snapshot.c
index c1a3604c261c..4bb9b1c63cac 100644
--- a/drivers/hv/hv_snapshot.c
+++ b/drivers/hv/hv_snapshot.c
@@ -47,6 +47,7 @@ static struct {
 	struct vmbus_channel *recv_channel; /* chn we got the request */
 	u64 recv_req_id; /* request ID. */
 	struct hv_vss_msg  *msg; /* current message */
+	void *vss_context; /* for the channel callback */
 } vss_transaction;
 
 
@@ -73,6 +74,9 @@ static void vss_timeout_func(struct work_struct *dummy)
 	 */
 	pr_warn("VSS: timeout waiting for daemon to reply\n");
 	vss_respond_to_host(HV_E_FAIL);
+
+	hv_poll_channel(vss_transaction.vss_context,
+			hv_vss_onchannelcallback);
 }
 
 static void
@@ -85,13 +89,12 @@ vss_cn_callback(struct cn_msg *msg, struct netlink_skb_parms *nsp)
 	if (vss_msg->vss_hdr.operation == VSS_OP_REGISTER) {
 		pr_info("VSS daemon registered\n");
 		vss_transaction.active = false;
-		if (vss_transaction.recv_channel != NULL)
-			hv_vss_onchannelcallback(vss_transaction.recv_channel);
-		return;
-
 	}
 	if (cancel_delayed_work_sync(&vss_timeout_work))
 		vss_respond_to_host(vss_msg->error);
+
+	hv_poll_channel(vss_transaction.vss_context,
+			hv_vss_onchannelcallback);
 }
 
 
@@ -198,9 +201,10 @@ void hv_vss_onchannelcallback(void *context)
 		 * We will defer processing this callback once
 		 * the current transaction is complete.
 		 */
-		vss_transaction.recv_channel = channel;
+		vss_transaction.vss_context = context;
 		return;
 	}
+	vss_transaction.vss_context = NULL;
 
 	vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
 			 &requestid);
-- 
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