From 7b79c52f3e8d783b98915fc6066daf9c4394f929 Mon Sep 17 00:00:00 2001
From: Dexuan Cui <decui@microsoft.com>
Date: Mon, 14 Dec 2015 16:01:51 -0800
Subject: [PATCH 17/41] Drivers: hv: vmbus: channge
 vmbus_connection.channel_lock to mutex

spinlock is unnecessary here.
mutex is enough.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit d6f591e339d23f434efda11917da511870891472)
---
 drivers/hv/channel_mgmt.c | 12 ++++++------
 drivers/hv/connection.c   |  7 +++----
 drivers/hv/hyperv_vmbus.h |  2 +-
 3 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 9c9da3a..d013171 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -206,9 +206,9 @@ void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid)
 	}
 
 	if (channel->primary_channel == NULL) {
-		spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
+		mutex_lock(&vmbus_connection.channel_mutex);
 		list_del(&channel->listentry);
-		spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
+		mutex_unlock(&vmbus_connection.channel_mutex);
 
 		primary_channel = channel;
 	} else {
@@ -253,7 +253,7 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
 	unsigned long flags;
 
 	/* Make sure this is a new offer */
-	spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
+	mutex_lock(&vmbus_connection.channel_mutex);
 
 	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 		if (!uuid_le_cmp(channel->offermsg.offer.if_type,
@@ -269,7 +269,7 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
 		list_add_tail(&newchannel->listentry,
 			      &vmbus_connection.chn_list);
 
-	spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
+	mutex_unlock(&vmbus_connection.channel_mutex);
 
 	if (!fnew) {
 		/*
@@ -341,9 +341,9 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel)
 err_deq_chan:
 	vmbus_release_relid(newchannel->offermsg.child_relid);
 
-	spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
+	mutex_lock(&vmbus_connection.channel_mutex);
 	list_del(&newchannel->listentry);
-	spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
+	mutex_unlock(&vmbus_connection.channel_mutex);
 
 	if (newchannel->target_cpu != get_cpu()) {
 		put_cpu();
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 4fc2e88..521f48e 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -146,7 +146,7 @@ int vmbus_connect(void)
 	spin_lock_init(&vmbus_connection.channelmsg_lock);
 
 	INIT_LIST_HEAD(&vmbus_connection.chn_list);
-	spin_lock_init(&vmbus_connection.channel_lock);
+	mutex_init(&vmbus_connection.channel_mutex);
 
 	/*
 	 * Setup the vmbus event connection for channel interrupt
@@ -282,11 +282,10 @@ struct vmbus_channel *relid2channel(u32 relid)
 {
 	struct vmbus_channel *channel;
 	struct vmbus_channel *found_channel  = NULL;
-	unsigned long flags;
 	struct list_head *cur, *tmp;
 	struct vmbus_channel *cur_sc;
 
-	spin_lock_irqsave(&vmbus_connection.channel_lock, flags);
+	mutex_lock(&vmbus_connection.channel_mutex);
 	list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
 		if (channel->offermsg.child_relid == relid) {
 			found_channel = channel;
@@ -305,7 +304,7 @@ struct vmbus_channel *relid2channel(u32 relid)
 			}
 		}
 	}
-	spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
+	mutex_unlock(&vmbus_connection.channel_mutex);
 
 	return found_channel;
 }
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 3782636..d9937be 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -678,7 +678,7 @@ struct vmbus_connection {
 
 	/* List of channels */
 	struct list_head chn_list;
-	spinlock_t channel_lock;
+	struct mutex channel_mutex;
 
 	struct workqueue_struct *work_queue;
 };
-- 
2.8.2

