[Drbd-dev] [PATCH 12/26] bcache: convert to blk_alloc_disk/blk_cleanup_disk

[Coly Li]

On 5/21/21 1:51 PM, Christoph Hellwig wrote:
> Convert the bcache driver to use the blk_alloc_disk and blk_cleanup_disk
> helpers to simplify gendisk and request_queue allocation.
> 
> Signed-off-by: Christoph Hellwig <hch at lst.de>
> ---
>  drivers/md/bcache/super.c | 15 ++++-----------
>  1 file changed, 4 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index bea8c4429ae8..185246a0d855 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -890,13 +890,9 @@ static void bcache_device_free(struct bcache_device *d)
>  		if (disk_added)
>  			del_gendisk(disk);
>  
> -		if (disk->queue)
> -			blk_cleanup_queue(disk->queue);
> -
> +		blk_cleanup_disk(disk);
>  		ida_simple_remove(&bcache_device_idx,
>  				  first_minor_to_idx(disk->first_minor));
> -		if (disk_added)
> -			put_disk(disk);

The  above 2 lines are added on purpose to prevent an refcount
underflow. It is from commit 86da9f736740 ("bcache: fix refcount
underflow in bcache_device_free()").

Maybe add a parameter to blk_cleanup_disk() or checking (disk->flags &
GENHD_FL_UP) inside blk_cleanup_disk() ?

Coly Li


>  	}
>  
>  	bioset_exit(&d->bio_split);
> @@ -946,7 +942,7 @@ static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
>  			BIOSET_NEED_BVECS|BIOSET_NEED_RESCUER))
>  		goto err;
>  
> -	d->disk = alloc_disk(BCACHE_MINORS);
> +	d->disk = blk_alloc_disk(NUMA_NO_NODE);
>  	if (!d->disk)
>  		goto err;
>  
> @@ -955,14 +951,11 @@ static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
>  
>  	d->disk->major		= bcache_major;
>  	d->disk->first_minor	= idx_to_first_minor(idx);
> +	d->disk->minors		= BCACHE_MINORS;
>  	d->disk->fops		= ops;
>  	d->disk->private_data	= d;
>  
> -	q = blk_alloc_queue(NUMA_NO_NODE);
> -	if (!q)
> -		return -ENOMEM;
> -
> -	d->disk->queue			= q;
> +	q = d->disk->queue;
>  	q->limits.max_hw_sectors	= UINT_MAX;
>  	q->limits.max_sectors		= UINT_MAX;
>  	q->limits.max_segment_size	= UINT_MAX;
> 

The rested looks fine to me.

Thanks.

Coly Li