# HG changeset patch
# User Daniel Stodden <daniel.stodden@xxxxxxxxxx>
# Date 1272506749 25200
# Node ID a781d46d987f8f8a9308412ba50bad4654a3d97c
# Parent  b324514f8f83ef0d8c7991e2c995400937c540ac
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@xxxxxxxxxx>

diff -r b324514f8f83 -r a781d46d987f drivers/block/xen-blkfront.c
--- a/drivers/block/xen-blkfront.c	Wed Apr 28 19:05:49 2010 -0700
+++ b/drivers/block/xen-blkfront.c	Wed Apr 28 19:05:49 2010 -0700
@@ -1075,18 +1075,41 @@
 	}
 }
 
-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;
 
-	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);
+
+	if (info->gd)
+		bdev = bdget_disk(info->gd, 0);
+
+	info->xbdev = NULL;
+	mutex_unlock(&info->mutex);
+
+	if (!bdev)
+		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, then release will take care of it.
+	 */
+
+	mutex_lock(&bdev->bd_mutex);
+
+	if (!info->users) {
+		xlvbd_release_gendisk(info);
 		kfree(info);
-	else
-		info->xbdev = NULL;
+	}
+
+	mutex_unlock(&bdev->bd_mutex);
+	bdput(bdev);
 
 	return 0;
 }