Re: [PATCH v4 2/5] mmc: move 'parent' tracking to mmc_blk_data

[Bart Van Assche]

On 06/21/2016 10:46 PM, Dan Williams wrote:
> In preparation for the removal of 'driverfs_dev' from 'struct gendisk',
> carry this data in mmc_blk_data. It is used for registration of parent
> disks and partitions.
>
> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Reported-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> ---
>  drivers/mmc/card/block.c |    5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 383184743f9a..d1733424bf6e 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -93,6 +93,7 @@ static DEFINE_SPINLOCK(mmc_blk_lock);
>   */
>  struct mmc_blk_data {
>  	spinlock_t	lock;
> +	struct device	*parent;
>  	struct gendisk	*disk;
>  	struct mmc_queue queue;
>  	struct list_head part;
> @@ -2270,7 +2271,7 @@ again:
>  	md->disk->fops = &mmc_bdops;
>  	md->disk->private_data = md;
>  	md->disk->queue = md->queue.queue;
> -	md->disk->driverfs_dev = parent;
> +	md->parent = parent;
>  	set_disk_ro(md->disk, md->read_only || default_ro);
>  	md->disk->flags = GENHD_FL_EXT_DEVT;
>  	if (area_type & (MMC_BLK_DATA_AREA_RPMB | MMC_BLK_DATA_AREA_BOOT))
> @@ -2458,7 +2459,7 @@ static int mmc_add_disk(struct mmc_blk_data *md)
>  	int ret;
>  	struct mmc_card *card = md->queue.card;
>
> -	add_disk(md->disk);
> +	device_add_disk(md->parent, md->disk);
>  	md->force_ro.show = force_ro_show;
>  	md->force_ro.store = force_ro_store;
>  	sysfs_attr_init(&md->force_ro.attr);

What will the impact be of this patch on code that accesses driverfs_dev 
like printk_all_partitions()? Will this patch hurt bisectability?

Thanks,

Bart.