staging: hv: convert channel_mgmt.c to not call osd_schedule_callback

The additional abstraction is unneeded.

The three calls are assumed to not be pending simultaneously:
 - vmbus_onoffer queues work exactly once when a new channel is
   created, the channel is not attached to lists until the work
   is executed
 - vmbus_onoffer_rescind is received only when the channel is
   active it is enough to process the work once
 - free_channel is called exactly once when the channel is getting
   destroyed; I assumed that vmbus_process_rescind_offer cannot be
   pending while free_channel is called

Reviewed-By: Hank Janssen <hjanssen@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 31 insertions, 22 deletions

diff --git a/drivers/staging/hv/channel_mgmt.c b/drivers/staging/hv/channel_mgmt.c
index 6f393e7d8e25..d44d5c39f68b 100644
--- a/drivers/staging/hv/channel_mgmt.c
+++ b/drivers/staging/hv/channel_mgmt.c
@@ -263,9 +263,11 @@ static struct vmbus_channel *alloc_channel(void)
 /*
  * release_hannel - Release the vmbus channel object itself
  */
-static inline void release_channel(void *context)
+static void release_channel(struct work_struct *work)
 {
-        struct vmbus_channel *channel = context;
+        struct vmbus_channel *channel = container_of(work,
+                                                     struct vmbus_channel,
+                                                     work);
 
         DPRINT_DBG(VMBUS, "releasing channel (%p)", channel);
         destroy_workqueue(channel->controlwq);
@@ -286,8 +288,8 @@ void free_channel(struct vmbus_channel *channel)
          * workqueue/thread context
          * ie we can't destroy ourselves.
          */
-        osd_schedule_callback(gVmbusConnection.WorkQueue, release_channel,
-                              channel);
+        INIT_WORK(&channel->work, release_channel);
+        queue_work(gVmbusConnection.WorkQueue, &channel->work);
 }
 
 
@@ -308,20 +310,37 @@ static void count_hv_channel(void)
         spin_unlock_irqrestore(&gVmbusConnection.channel_lock, flags);
 }
 
+/*
+ * vmbus_process_rescind_offer -
+ * Rescind the offer by initiating a device removal
+ */
+static void vmbus_process_rescind_offer(struct work_struct *work)
+{
+        struct vmbus_channel *channel = container_of(work,
+                                                     struct vmbus_channel,
+                                                     work);
+
+        vmbus_child_device_unregister(channel->device_obj);
+}
 
 /*
  * vmbus_process_offer - Process the offer by creating a channel/device
  * associated with this offer
  */
-static void vmbus_process_offer(void *context)
+static void vmbus_process_offer(struct work_struct *work)
 {
-        struct vmbus_channel *newchannel = context;
+        struct vmbus_channel *newchannel = container_of(work,
+                                                        struct vmbus_channel,
+                                                        work);
         struct vmbus_channel *channel;
         bool fnew = true;
         int ret;
         int cnt;
         unsigned long flags;
 
+        /* The next possible work is rescind handling */
+        INIT_WORK(&newchannel->work, vmbus_process_rescind_offer);
+
         /* Make sure this is a new offer */
         spin_lock_irqsave(&gVmbusConnection.channel_lock, flags);
 
@@ -406,17 +425,6 @@ static void vmbus_process_offer(void *context)
 }
 
 /*
- * vmbus_process_rescind_offer -
- * Rescind the offer by initiating a device removal
- */
-static void vmbus_process_rescind_offer(void *context)
-{
-        struct vmbus_channel *channel = context;
-
-        vmbus_child_device_unregister(channel->device_obj);
-}
-
-/*
  * vmbus_onoffer - Handler for channel offers from vmbus in parent partition.
  *
  * We ignore all offers except network and storage offers. For each network and
@@ -490,8 +498,8 @@ static void vmbus_onoffer(struct vmbus_channel_message_header *hdr)
         newchannel->monitor_bit = (u8)offer->monitorid % 32;
 
         /* TODO: Make sure the offer comes from our parent partition */
-        osd_schedule_callback(newchannel->controlwq, vmbus_process_offer,
-                              newchannel);
+        INIT_WORK(&newchannel->work, vmbus_process_offer);
+        queue_work(newchannel->controlwq, &newchannel->work);
 }
 
 /*
@@ -512,9 +520,9 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr)
                 return;
         }
 
-        osd_schedule_callback(channel->controlwq,
-                              vmbus_process_rescind_offer,
-                              channel);
+        /* work is initialized for vmbus_process_rescind_offer() from
+         * vmbus_process_offer() where the channel got created */
+        queue_work(channel->controlwq, &channel->work);
 }
 
 /*
diff --git a/drivers/staging/hv/channel_mgmt.h b/drivers/staging/hv/channel_mgmt.h
index 12f30aff152d..de6b2a0ebf70 100644
--- a/drivers/staging/hv/channel_mgmt.h
+++ b/drivers/staging/hv/channel_mgmt.h
@@ -231,6 +231,7 @@ struct vmbus_channel {
         struct hv_device *device_obj;
 
         struct timer_list poll_timer; /* SA-111 workaround */
+        struct work_struct work;
 
         enum vmbus_channel_state state;