blkfront: Clean up vbd release

 * Current blkfront_closing is rather a xlvbd_release_gendisk.
   Renamed in preparation of later patches (need the name again).

 * Removed the misleading comment -- this only applied to the backend
   switch handler, and the queue is already flushed btw.

 * Break out the xenbus call, callers know better when to switch
   frontend state.

Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 43 insertions, 48 deletions

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 62d32959095d..d4cb7fd82b4c 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -534,6 +534,39 @@ static int xlvbd_alloc_gendisk(blkif_sector_t capacity,
         return err;
 }
 
+static void xlvbd_release_gendisk(struct blkfront_info *info)
+{
+        unsigned int minor, nr_minors;
+        unsigned long flags;
+
+        if (info->rq == NULL)
+                return;
+
+        spin_lock_irqsave(&blkif_io_lock, flags);
+
+        /* No more blkif_request(). */
+        blk_stop_queue(info->rq);
+
+        /* No more gnttab callback work. */
+        gnttab_cancel_free_callback(&info->callback);
+        spin_unlock_irqrestore(&blkif_io_lock, flags);
+
+        /* Flush gnttab callback work. Must be done with no locks held. */
+        flush_scheduled_work();
+
+        del_gendisk(info->gd);
+
+        minor = info->gd->first_minor;
+        nr_minors = info->gd->minors;
+        xlbd_release_minors(minor, nr_minors);
+
+        blk_cleanup_queue(info->rq);
+        info->rq = NULL;
+
+        put_disk(info->gd);
+        info->gd = NULL;
+}
+
 static void kick_pending_request_queues(struct blkfront_info *info)
 {
         if (!RING_FULL(&info->ring)) {
@@ -995,49 +1028,6 @@ static void blkfront_connect(struct blkfront_info *info)
 }
 
 /**
- * Handle the change of state of the backend to Closing.  We must delete our
- * device-layer structures now, to ensure that writes are flushed through to
- * the backend.  Once is this done, we can switch to Closed in
- * acknowledgement.
- */
-static void blkfront_closing(struct blkfront_info *info)
-{
-        unsigned int minor, nr_minors;
-        unsigned long flags;
-
-
-        if (info->rq == NULL)
-                goto out;
-
-        spin_lock_irqsave(&blkif_io_lock, flags);
-
-        /* No more blkif_request(). */
-        blk_stop_queue(info->rq);
-
-        /* No more gnttab callback work. */
-        gnttab_cancel_free_callback(&info->callback);
-        spin_unlock_irqrestore(&blkif_io_lock, flags);
-
-        /* Flush gnttab callback work. Must be done with no locks held. */
-        flush_scheduled_work();
-
-        minor = info->gd->first_minor;
-        nr_minors = info->gd->minors;
-        del_gendisk(info->gd);
-        xlbd_release_minors(minor, nr_minors);
-
-        blk_cleanup_queue(info->rq);
-        info->rq = NULL;
-
-        put_disk(info->gd);
-        info->gd = NULL;
-
- out:
-        if (info->xbdev)
-                xenbus_frontend_closed(info->xbdev);
-}
-
-/**
  * Callback received when the backend's state changes.
  */
 static void blkback_changed(struct xenbus_device *dev,
@@ -1073,8 +1063,11 @@ static void blkback_changed(struct xenbus_device *dev,
                 if (info->users > 0)
                         xenbus_dev_error(dev, -EBUSY,
                                          "Device in use; refusing to close");
-                else
-                        blkfront_closing(info);
+                else {
+                        xlvbd_release_gendisk(info);
+                        xenbus_frontend_closed(info->xbdev);
+                }
+
                 mutex_unlock(&bd->bd_mutex);
                 bdput(bd);
                 break;
@@ -1130,11 +1123,13 @@ static int blkif_release(struct gendisk *disk, fmode_t mode)
                 struct xenbus_device *dev = info->xbdev;
 
                 if (!dev) {
-                        blkfront_closing(info);
+                        xlvbd_release_gendisk(info);
                         kfree(info);
                 } else if (xenbus_read_driver_state(dev->otherend)
-                           == XenbusStateClosing && info->is_ready)
-                        blkfront_closing(info);
+                           == XenbusStateClosing && info->is_ready) {
+                        xlvbd_release_gendisk(info);
+                        xenbus_frontend_closed(dev);
+                }
         }
         unlock_kernel();
         return 0;