Re: [PATCH 3/9] block: factor out a bd_end_claim helper from blkdev_put

[Jan Kara <jack@suse.cz>]

On Fri 05-05-23 13:51:26, Christoph Hellwig wrote:
> Move all the logic to release an exclusive claim into a helper.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Nice. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  block/bdev.c | 63 +++++++++++++++++++++++++++-------------------------
>  1 file changed, 33 insertions(+), 30 deletions(-)
> 
> diff --git a/block/bdev.c b/block/bdev.c
> index 850852fe4b78e1..f2c7181b0bba7d 100644
> --- a/block/bdev.c
> +++ b/block/bdev.c
> @@ -578,6 +578,37 @@ void bd_abort_claiming(struct block_device *bdev, void *holder)
>  }
>  EXPORT_SYMBOL(bd_abort_claiming);
>  
> +static void bd_end_claim(struct block_device *bdev)
> +{
> +	struct block_device *whole = bdev_whole(bdev);
> +	bool unblock = false;
> +
> +	/*
> +	 * Release a claim on the device.  The holder fields are protected with
> +	 * bdev_lock.  open_mutex is used to synchronize disk_holder unlinking.
> +	 */
> +	spin_lock(&bdev_lock);
> +	WARN_ON_ONCE(--bdev->bd_holders < 0);
> +	WARN_ON_ONCE(--whole->bd_holders < 0);
> +	if (!bdev->bd_holders) {
> +		bdev->bd_holder = NULL;
> +		if (bdev->bd_write_holder)
> +			unblock = true;
> +	}
> +	if (!whole->bd_holders)
> +		whole->bd_holder = NULL;
> +	spin_unlock(&bdev_lock);
> +
> +	/*
> +	 * If this was the last claim, remove holder link and unblock evpoll if
> +	 * it was a write holder.
> +	 */
> +	if (unblock) {
> +		disk_unblock_events(bdev->bd_disk);
> +		bdev->bd_write_holder = false;
> +	}
> +}
> +
>  static void blkdev_flush_mapping(struct block_device *bdev)
>  {
>  	WARN_ON_ONCE(bdev->bd_holders);
> @@ -832,36 +863,8 @@ void blkdev_put(struct block_device *bdev, fmode_t mode)
>  		sync_blockdev(bdev);
>  
>  	mutex_lock(&disk->open_mutex);
> -	if (mode & FMODE_EXCL) {
> -		struct block_device *whole = bdev_whole(bdev);
> -		bool bdev_free;
> -
> -		/*
> -		 * Release a claim on the device.  The holder fields
> -		 * are protected with bdev_lock.  open_mutex is to
> -		 * synchronize disk_holder unlinking.
> -		 */
> -		spin_lock(&bdev_lock);
> -
> -		WARN_ON_ONCE(--bdev->bd_holders < 0);
> -		WARN_ON_ONCE(--whole->bd_holders < 0);
> -
> -		if ((bdev_free = !bdev->bd_holders))
> -			bdev->bd_holder = NULL;
> -		if (!whole->bd_holders)
> -			whole->bd_holder = NULL;
> -
> -		spin_unlock(&bdev_lock);
> -
> -		/*
> -		 * If this was the last claim, remove holder link and
> -		 * unblock evpoll if it was a write holder.
> -		 */
> -		if (bdev_free && bdev->bd_write_holder) {
> -			disk_unblock_events(disk);
> -			bdev->bd_write_holder = false;
> -		}
> -	}
> +	if (mode & FMODE_EXCL)
> +		bd_end_claim(bdev);
>  
>  	/*
>  	 * Trigger event checking and tell drivers to flush MEDIA_CHANGE
> -- 
> 2.39.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR