From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>
Cc: Josef Bacik <josef@toxicpanda.com>,
David Sterba <dsterba@suse.com>,
linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: [PATCH 3/8] block: grab a device model reference in blkdev_get_no_open
Date: Wed, 21 Jul 2021 17:35:18 +0200 [thread overview]
Message-ID: <20210721153523.103818-4-hch@lst.de> (raw)
In-Reply-To: <20210721153523.103818-1-hch@lst.de>
Opening a block device needs to ensure it is fully present instead of
just the allocated memory. Switch from an inode reference as obtained
by bdget to a full device model reference.
In fact we should not use inode references for anything in the block
layer. There are three users left, two can be trivially removed
and the third (xen-blkfront) is a complete mess that needs more
attention.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/block_dev.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 9ef4f1fc2cb0..24a6970f3623 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1342,9 +1342,16 @@ struct block_device *blkdev_get_no_open(dev_t dev)
goto bdput;
if ((disk->flags & (GENHD_FL_UP | GENHD_FL_HIDDEN)) != GENHD_FL_UP)
goto put_disk;
- if (!try_module_get(bdev->bd_disk->fops->owner))
+ if (!try_module_get(disk->fops->owner))
goto put_disk;
+
+ /* switch to a device model reference instead of the inode one: */
+ if (!kobject_get_unless_zero(&bdev->bd_device.kobj))
+ goto put_module;
+ bdput(bdev);
return bdev;
+put_module:
+ module_put(disk->fops->owner);
put_disk:
put_disk(disk);
bdput:
@@ -1356,7 +1363,7 @@ void blkdev_put_no_open(struct block_device *bdev)
{
module_put(bdev->bd_disk->fops->owner);
put_disk(bdev->bd_disk);
- bdput(bdev);
+ put_device(&bdev->bd_device);
}
/**
--
2.30.2
next prev parent reply other threads:[~2021-07-21 15:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-21 15:35 fixes and cleanups for block_device refcounting Christoph Hellwig
2021-07-21 15:35 ` [PATCH 1/8] block: delay freeing the gendisk Christoph Hellwig
2021-07-22 2:05 ` Ming Lei
2021-07-21 15:35 ` [PATCH 2/8] block: assert the locking state in delete_partition Christoph Hellwig
2021-07-22 2:06 ` Ming Lei
2021-07-21 15:35 ` Christoph Hellwig [this message]
2021-07-22 2:47 ` [PATCH 3/8] block: grab a device model reference in blkdev_get_no_open Ming Lei
2021-07-21 15:35 ` [PATCH 4/8] block: don't grab a reference to the whole device in blkdev_get_part Christoph Hellwig
2021-07-21 15:35 ` [PATCH 5/8] btrfs: no need to grab a reference to disk->part0 Christoph Hellwig
2021-07-21 16:15 ` David Sterba
2021-07-21 15:35 ` [PATCH 6/8] loop: don't grab a reference to the block device Christoph Hellwig
2021-07-21 15:35 ` [PATCH 7/8] block: remove bdgrab Christoph Hellwig
2021-07-21 15:35 ` [PATCH 8/8] block: remove bdget/bdput Christoph Hellwig
2021-07-21 20:52 ` fixes and cleanups for block_device refcounting Josef Bacik
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