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>

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 62d32959095d22c92b55545b5c8dba05b30843c7..d4cb7fd82b4c6fbdb346051d8d01b8677a5d84ea 100644 (file)
--- 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)) {
@@ -994,49 +1027,6 @@ static void blkfront_connect(struct blkfront_info *info)
        info->is_ready = 1;
 }
 
-/**
- * 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.
  */
@@ -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;