Re: [PATCH 6/8] bdi: remove bdi_register_owner

From: Jan Kara
Date: Thu Apr 16 2020 - 08:05:58 EST


On Thu 16-04-20 09:15:17, Christoph Hellwig wrote:
> Split out a new bdi_set_owner helper to set the owner, and move the policy
> for creating the bdi name back into genhd.c, where it belongs.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>

Fine by me. You can add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

Honza

> ---
> block/genhd.c | 8 +++++---
> include/linux/backing-dev.h | 2 +-
> mm/backing-dev.c | 12 ++----------
> 3 files changed, 8 insertions(+), 14 deletions(-)
>
> diff --git a/block/genhd.c b/block/genhd.c
> index 06b642b23a07..7d10cfc38c70 100644
> --- a/block/genhd.c
> +++ b/block/genhd.c
> @@ -840,13 +840,15 @@ static void __device_add_disk(struct device *parent, struct gendisk *disk,
> disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
> disk->flags |= GENHD_FL_NO_PART_SCAN;
> } else {
> + struct backing_dev_info *bdi = disk->queue->backing_dev_info;
> + struct device *dev = disk_to_dev(disk);
> int ret;
>
> /* Register BDI before referencing it from bdev */
> - disk_to_dev(disk)->devt = devt;
> - ret = bdi_register_owner(disk->queue->backing_dev_info,
> - disk_to_dev(disk));
> + dev->devt = devt;
> + ret = bdi_register(bdi, "%u:%u", MAJOR(devt), MINOR(devt));
> WARN_ON(ret);
> + bdi_set_owner(bdi, dev);
> blk_register_region(disk_devt(disk), disk->minors, NULL,
> exact_match, exact_lock, disk);
> }
> diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
> index c9ad5c3b7b4b..4098ed6ba6b4 100644
> --- a/include/linux/backing-dev.h
> +++ b/include/linux/backing-dev.h
> @@ -33,7 +33,7 @@ int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...);
> __printf(2, 0)
> int bdi_register_va(struct backing_dev_info *bdi, const char *fmt,
> va_list args);
> -int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner);
> +void bdi_set_owner(struct backing_dev_info *bdi, struct device *owner);
> void bdi_unregister(struct backing_dev_info *bdi);
>
> struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id);
> diff --git a/mm/backing-dev.c b/mm/backing-dev.c
> index a7eb91146c9c..1ba9a7b30933 100644
> --- a/mm/backing-dev.c
> +++ b/mm/backing-dev.c
> @@ -982,20 +982,12 @@ int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...)
> }
> EXPORT_SYMBOL(bdi_register);
>
> -int bdi_register_owner(struct backing_dev_info *bdi, struct device *owner)
> +void bdi_set_owner(struct backing_dev_info *bdi, struct device *owner)
> {
> - int rc;
> -
> - rc = bdi_register(bdi, "%u:%u", MAJOR(owner->devt), MINOR(owner->devt));
> - if (rc)
> - return rc;
> - /* Leaking owner reference... */
> - WARN_ON(bdi->owner);
> + WARN_ON_ONCE(bdi->owner);
> bdi->owner = owner;
> get_device(owner);
> - return 0;
> }
> -EXPORT_SYMBOL(bdi_register_owner);
>
> /*
> * Remove bdi from bdi_list, and ensure that it is no longer visible
> --
> 2.25.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR