From: Zhaolei <zhaolei@cn.fujitsu.com>
Date: Fri, 14 Nov 2008 08:44:33 +0000 (+0100)
Subject: Release old elevator on change elevator
X-Git-Tag: v2.6.28-rc6~51^2~2
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=68aee07f9bad2c830a898cf6d6bfc11ea24efc40;p=linux-2.6-omap-h63xx.git

Release old elevator on change elevator

We should release old elevator when change to use a new one.

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index b220c686089..2d19f0cc47f 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -338,12 +338,18 @@ wait:
 static int xlvbd_init_blk_queue(struct gendisk *gd, u16 sector_size)
 {
 	struct request_queue *rq;
+	elevator_t *old_e;
 
 	rq = blk_init_queue(do_blkif_request, &blkif_io_lock);
 	if (rq == NULL)
 		return -1;
 
-	elevator_init(rq, "noop");
+	old_e = rq->elevator;
+	if (IS_ERR_VALUE(elevator_init(rq, "noop")))
+		printk(KERN_WARNING
+			"blkfront: Switch elevator failed, use default\n");
+	else
+		elevator_exit(old_e);
 
 	/* Hard sector size and max sectors impersonate the equiv. hardware. */
 	blk_queue_hardsect_size(rq, sector_size);