blkfront: Lock blockfront_info during xbdev removal
Same approach as blkfront_closing:
* Grab the bdev safely, holding the info mutex.
* Zap xbdev safely, holding the info mutex.
* Try bdev removal safely, holding bd_mutex.
Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 4986299..715de7d 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1093,18 +1093,47 @@
}
}
-static int blkfront_remove(struct xenbus_device *dev)
+static int blkfront_remove(struct xenbus_device *xbdev)
{
- struct blkfront_info *info = dev_get_drvdata(&dev->dev);
+ struct blkfront_info *info = dev_get_drvdata(&xbdev->dev);
+ struct block_device *bdev = NULL;
+ struct gendisk *disk;
- dev_dbg(&dev->dev, "blkfront_remove: %s removed\n", dev->nodename);
+ dev_dbg(&xbdev->dev, "%s removed", xbdev->nodename);
blkif_free(info, 0);
- if(info->users == 0)
+ mutex_lock(&info->mutex);
+
+ disk = info->gd;
+ if (disk)
+ bdev = bdget_disk(disk, 0);
+
+ info->xbdev = NULL;
+ mutex_unlock(&info->mutex);
+
+ if (!bdev) {
kfree(info);
- else
- info->xbdev = NULL;
+ return 0;
+ }
+
+ /*
+ * The xbdev was removed before we reached the Closed
+ * state. See if it's safe to remove the disk. If the bdev
+ * isn't closed yet, we let release take care of it.
+ */
+
+ mutex_lock(&bdev->bd_mutex);
+ info = disk->private_data;
+
+ if (info && !info->users) {
+ xlvbd_release_gendisk(info);
+ disk->private_data = NULL;
+ kfree(info);
+ }
+
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(bdev);
return 0;
}