[3.11.y.z extended stable] Patch "Drivers: hv: util: Fix a bug in the KVP code" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    Drivers: hv: util: Fix a bug in the KVP code

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From a21acf8d9c85b3e581c5306a42b041e2d2238aa5 Mon Sep 17 00:00:00 2001
From: "K. Y. Srinivasan" <kys at microsoft.com>
Date: Mon, 7 Jul 2014 16:34:25 -0700
Subject: Drivers: hv: util: Fix a bug in the KVP code

commit 9bd2d0dfe4714dd5d7c09a93a5c9ea9e14ceb3fc upstream.

Add code to poll the channel since we process only one message
at a time and the host may not interrupt us. Also increase the
receive buffer size since some KVP messages are close to 8K bytes in size.

Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
[ luis: backported to 3.11: used kys's backport for 3.15 ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/hv/hv_kvp.c  | 16 +++++++++++++---
 drivers/hv/hv_util.c |  2 +-
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/hv/hv_kvp.c b/drivers/hv/hv_kvp.c
index ed50e9e83c61..cf2bd4aeb404 100644
--- a/drivers/hv/hv_kvp.c
+++ b/drivers/hv/hv_kvp.c
@@ -111,6 +111,16 @@ kvp_work_func(struct work_struct *dummy)
 	kvp_respond_to_host(NULL, HV_E_FAIL);
 }

+static void poll_channel(struct vmbus_channel *channel)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&channel->inbound_lock, flags);
+	hv_kvp_onchannelcallback(channel);
+	spin_unlock_irqrestore(&channel->inbound_lock, flags);
+}
+
+
 static int kvp_handle_handshake(struct hv_kvp_msg *msg)
 {
 	int ret = 1;
@@ -139,7 +149,7 @@ static int kvp_handle_handshake(struct hv_kvp_msg *msg)
 		kvp_register(dm_reg_value);
 		kvp_transaction.active = false;
 		if (kvp_transaction.kvp_context)
-			hv_kvp_onchannelcallback(kvp_transaction.kvp_context);
+			poll_channel(kvp_transaction.kvp_context);
 	}
 	return ret;
 }
@@ -552,7 +562,7 @@ response_done:

 	vmbus_sendpacket(channel, recv_buffer, buf_len, req_id,
 				VM_PKT_DATA_INBAND, 0);
-
+	poll_channel(channel);
 }

 /*
@@ -585,7 +595,7 @@ void hv_kvp_onchannelcallback(void *context)
 		return;
 	}

-	vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen,
+	vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 4, &recvlen,
 			 &requestid);

 	if (recvlen > 0) {
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 2f561c5dfe24..64c778f7756f 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -279,7 +279,7 @@ static int util_probe(struct hv_device *dev,
 		(struct hv_util_service *)dev_id->driver_data;
 	int ret;

-	srv->recv_buffer = kmalloc(PAGE_SIZE * 2, GFP_KERNEL);
+	srv->recv_buffer = kmalloc(PAGE_SIZE * 4, GFP_KERNEL);
 	if (!srv->recv_buffer)
 		return -ENOMEM;
 	if (srv->util_init) {
--
1.9.1