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blkfront: Lock blockfront_info during xbdev removal

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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>
This commit is contained in:
Daniel Stodden 2010-04-30 22:01:22 +00:00 committed by Jens Axboe
parent 7fd152f4b6
commit fa1bd3591a
1 changed files with 35 additions and 6 deletions
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41
drivers/block/xen-blkfront.c
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@ -1093,18 +1093,47 @@ static void blkback_changed(struct xenbus_device *dev,
}
}
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)
kfree(info);
else
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);
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;
}