Drivers: hv: rename sc_lock to the more generic lock

sc_lock spinlock in struct vmbus_channel is being used to not only protect the
sc_list field, e.g. vmbus_open() function uses it to implement test-and-set
access to the state field. Rename it to the more generic 'lock' and add the
description.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 14 insertions, 9 deletions

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 18c4f23dacf1..2978f5ee8d2a 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -73,14 +73,14 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size,
         unsigned long flags;
         int ret, t, err = 0;
 
-        spin_lock_irqsave(&newchannel->sc_lock, flags);
+        spin_lock_irqsave(&newchannel->lock, flags);
         if (newchannel->state == CHANNEL_OPEN_STATE) {
                 newchannel->state = CHANNEL_OPENING_STATE;
         } else {
-                spin_unlock_irqrestore(&newchannel->sc_lock, flags);
+                spin_unlock_irqrestore(&newchannel->lock, flags);
                 return -EINVAL;
         }
-        spin_unlock_irqrestore(&newchannel->sc_lock, flags);
+        spin_unlock_irqrestore(&newchannel->lock, flags);
 
         newchannel->onchannel_callback = onchannelcallback;
         newchannel->channel_callback_context = context;
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 704c0e00f8d2..1e0b996ed643 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -146,7 +146,7 @@ static struct vmbus_channel *alloc_channel(void)
                 return NULL;
 
         spin_lock_init(&channel->inbound_lock);
-        spin_lock_init(&channel->sc_lock);
+        spin_lock_init(&channel->lock);
 
         INIT_LIST_HEAD(&channel->sc_list);
         INIT_LIST_HEAD(&channel->percpu_list);
@@ -246,9 +246,9 @@ static void vmbus_process_rescind_offer(struct work_struct *work)
                 spin_unlock_irqrestore(&vmbus_connection.channel_lock, flags);
         } else {
                 primary_channel = channel->primary_channel;
-                spin_lock_irqsave(&primary_channel->sc_lock, flags);
+                spin_lock_irqsave(&primary_channel->lock, flags);
                 list_del(&channel->sc_list);
-                spin_unlock_irqrestore(&primary_channel->sc_lock, flags);
+                spin_unlock_irqrestore(&primary_channel->lock, flags);
         }
         free_channel(channel);
 }
@@ -323,9 +323,9 @@ static void vmbus_process_offer(struct work_struct *work)
                          * Process the sub-channel.
                          */
                         newchannel->primary_channel = channel;
-                        spin_lock_irqsave(&channel->sc_lock, flags);
+                        spin_lock_irqsave(&channel->lock, flags);
                         list_add_tail(&newchannel->sc_list, &channel->sc_list);
-                        spin_unlock_irqrestore(&channel->sc_lock, flags);
+                        spin_unlock_irqrestore(&channel->lock, flags);
 
                         if (newchannel->target_cpu != get_cpu()) {
                                 put_cpu();
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 259023a34bec..5a2ba674795e 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -734,7 +734,12 @@ struct vmbus_channel {
          */
         void (*sc_creation_callback)(struct vmbus_channel *new_sc);
 
-        spinlock_t sc_lock;
+        /*
+         * The spinlock to protect the structure. It is being used to protect
+         * test-and-set access to various attributes of the structure as well
+         * as all sc_list operations.
+         */
+        spinlock_t lock;
         /*
          * All Sub-channels of a primary channel are linked here.
          */