diff mbox series

[RFC,v3,05/10] dm: make sure create and remove dm device won't race with open and close table

Message ID 20221115141054.1051801-6-yukuai1@huaweicloud.com
State New
Headers
Series fix delayed holder tracking |

Commit Message

Yu Kuai Nov. 15, 2022, 2:10 p.m. UTC 
  From: Yu Kuai <yukuai3@huawei.com>

open_table_device() and close_table_device() is protected by
table_devices_lock, hence use it to protect add_disk() and
del_gendisk().

Prepare to track per-add_disk holder relations in dm.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
 drivers/md/dm.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

Comments

Christoph Hellwig Nov. 16, 2022, 6:35 a.m. UTC | #1 
Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>
Mike Snitzer Nov. 16, 2022, 9:48 p.m. UTC | #2 
On Tue, Nov 15 2022 at  9:10P -0500,
Yu Kuai <yukuai1@huaweicloud.com> wrote:

> From: Yu Kuai <yukuai3@huawei.com>
> 
> open_table_device() and close_table_device() is protected by
> table_devices_lock, hence use it to protect add_disk() and
> del_gendisk().
> 
> Prepare to track per-add_disk holder relations in dm.
> 
> Signed-off-by: Yu Kuai <yukuai3@huawei.com>
> ---
>  drivers/md/dm.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 2917700b1e15..3728b56b364b 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -1952,7 +1952,14 @@ static void cleanup_mapped_device(struct mapped_device *md)
>  		spin_unlock(&_minor_lock);
>  		if (dm_get_md_type(md) != DM_TYPE_NONE) {
>  			dm_sysfs_exit(md);
> +
> +			/*
> +			 * Hold lock to make sure del_gendisk() won't concurrent
> +			 * with open/close_table_device().
> +			 */
> +			mutex_lock(&md->table_devices_lock);
>  			del_gendisk(md->disk);
> +			mutex_unlock(&md->table_devices_lock);
>  		}
>  		dm_queue_destroy_crypto_profile(md->queue);
>  		put_disk(md->disk);
> @@ -2312,15 +2319,24 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
>  	if (r)
>  		return r;
>  
> +	/*
> +	 * Hold lock to make sure add_disk() and del_gendisk() won't concurrent
> +	 * with open_table_device() and close_table_device().
> +	 */
> +	mutex_lock(&md->table_devices_lock);
>  	r = add_disk(md->disk);
> +	mutex_unlock(&md->table_devices_lock);
>  	if (r)
>  		return r;
>  
>  	r = dm_sysfs_init(md);
>  	if (r) {
> +		mutex_lock(&md->table_devices_lock);
>  		del_gendisk(md->disk);
> +		mutex_unlock(&md->table_devices_lock);
>  		return r;
>  	}
> +
>  	md->type = type;
>  	return 0;
>  }
> -- 
> 2.31.1
> 

In the new comments added: s/concurrent/race/ ?

But otherwise:

Reviewed-by: Mike Snitzer <snitzer@kernel.org>
diff mbox series

Patch

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 2917700b1e15..3728b56b364b 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1952,7 +1952,14 @@  static void cleanup_mapped_device(struct mapped_device *md)
 		spin_unlock(&_minor_lock);
 		if (dm_get_md_type(md) != DM_TYPE_NONE) {
 			dm_sysfs_exit(md);
+
+			/*
+			 * Hold lock to make sure del_gendisk() won't concurrent
+			 * with open/close_table_device().
+			 */
+			mutex_lock(&md->table_devices_lock);
 			del_gendisk(md->disk);
+			mutex_unlock(&md->table_devices_lock);
 		}
 		dm_queue_destroy_crypto_profile(md->queue);
 		put_disk(md->disk);
@@ -2312,15 +2319,24 @@  int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
 	if (r)
 		return r;
 
+	/*
+	 * Hold lock to make sure add_disk() and del_gendisk() won't concurrent
+	 * with open_table_device() and close_table_device().
+	 */
+	mutex_lock(&md->table_devices_lock);
 	r = add_disk(md->disk);
+	mutex_unlock(&md->table_devices_lock);
 	if (r)
 		return r;
 
 	r = dm_sysfs_init(md);
 	if (r) {
+		mutex_lock(&md->table_devices_lock);
 		del_gendisk(md->disk);
+		mutex_unlock(&md->table_devices_lock);
 		return r;
 	}
+
 	md->type = type;
 	return 0;
 }