Re: [PATCH 6/8] dm: move setting md->type into dm_setup_md_queue

[Mike Snitzer <snitzer@redhat.com>]

On Sun, Jul 25 2021 at  1:54P -0400,
Christoph Hellwig <hch@lst.de> wrote:

> Move setting md->type from both callers into dm_setup_md_queue.
> This ensures that md->type is only set to a valid value after the queue
> has been fully setup, something we'll rely on future changes.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Reviewed-by: Mike Snitzer <snitzer@redhat.com>

> ---
>  drivers/md/dm-ioctl.c | 4 ----
>  drivers/md/dm.c       | 5 +++--
>  2 files changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
> index 2209cbcd84db..2575074a2204 100644
> --- a/drivers/md/dm-ioctl.c
> +++ b/drivers/md/dm-ioctl.c
> @@ -1436,9 +1436,6 @@ static int table_load(struct file *filp, struct dm_ioctl *param, size_t param_si
>  	}
>  
>  	if (dm_get_md_type(md) == DM_TYPE_NONE) {
> -		/* Initial table load: acquire type of table. */
> -		dm_set_md_type(md, dm_table_get_type(t));
> -
>  		/* setup md->queue to reflect md's type (may block) */
>  		r = dm_setup_md_queue(md, t);
>  		if (r) {
> @@ -2187,7 +2184,6 @@ int __init dm_early_create(struct dm_ioctl *dmi,
>  	if (r)
>  		goto err_destroy_table;
>  
> -	md->type = dm_table_get_type(t);
>  	/* setup md->queue to reflect md's type (may block) */
>  	r = dm_setup_md_queue(md, t);
>  	if (r) {
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 7971ec8ce677..f003bd5b93ce 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -2052,9 +2052,9 @@ EXPORT_SYMBOL_GPL(dm_get_queue_limits);
>   */
>  int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
>  {
> -	int r;
> +	enum dm_queue_mode type = dm_table_get_type(t);
>  	struct queue_limits limits;
> -	enum dm_queue_mode type = dm_get_md_type(md);
> +	int r;
>  
>  	switch (type) {
>  	case DM_TYPE_REQUEST_BASED:
> @@ -2081,6 +2081,7 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
>  	r = dm_table_set_restrictions(t, md->queue, &limits);
>  	if (r)
>  		return r;
> +	md->type = type;
>  
>  	blk_register_queue(md->disk);
>  
> -- 
> 2.30.2
>