Re: [PATCH 2/4] blkcg: Restructure blkg_conf_prep() and friends

[Christoph Hellwig]

On Thu, Jan 05, 2023 at 11:24:30AM -1000, Tejun Heo wrote:
> * blkg_conf_open_bdev() is updated to take a pointer to blkg_conf_ctx like
>   blkg_conf_prep() and can be called multiple times safely. Instead of
>   modifying the double pointer to input string directly,
>   blkg_conf_open_bdev() now sets blkg_conf_ctx->body.

This looks pretty awkward for the externals callers of blkcg_conf_open_bdev
in blk-iocost.  I'd either keep the calling conventions as they are
at the moment, or just open code blkcg_conf_open_bdev in blk-iocost.