Re: [PATCH] blk-throttle: Remove dead check in tg_conf_updated()

[Tao Cui]

在 2026/8/21 00:05, Tang Yizhou 写道:
> From: Tang Yizhou <yizhou.tang@xxxxxxxxxx>
> 
> The check in tg_conf_updated() was introduced for io.low, so remove it.
> 
> global ? tg->td->queue->root_blkg : tg_to_blkg(tg) was introduced in
> commit 9bb67aeb9678 ("blk-throttle: respect 0 bps/iops settings for
> io.low"). Remove it, too.
> 
> Fixes: bf20ab538c81 ("blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOW")
> Signed-off-by: Tang Yizhou <yizhou.tang@xxxxxxxxxx>
> ---
>  block/blk-throttle.c | 18 +++++-------------
>  1 file changed, 5 insertions(+), 13 deletions(-)
> 
> diff --git a/block/blk-throttle.c b/block/blk-throttle.c
> index ffc3b70065d4..fa742e63807d 100644
> --- a/block/blk-throttle.c
> +++ b/block/blk-throttle.c
> @@ -1267,7 +1267,7 @@ static int tg_print_conf_uint(struct seq_file *sf, void *v)
>  	return 0;
>  }
>  
> -static void tg_conf_updated(struct throtl_grp *tg, bool global)
> +static void tg_conf_updated(struct throtl_grp *tg)
>  {
>  	struct throtl_service_queue *sq = &tg->service_queue;
>  	struct cgroup_subsys_state *pos_css;
> @@ -1286,16 +1286,8 @@ static void tg_conf_updated(struct throtl_grp *tg, bool global)
>  	 * restrictions in the whole hierarchy and allows them to bypass
>  	 * blk-throttle.
>  	 */
> -	blkg_for_each_descendant_pre(blkg, pos_css,
> -			global ? tg->td->queue->root_blkg : tg_to_blkg(tg)) {
> -		struct throtl_grp *this_tg = blkg_to_tg(blkg);
> -
> -		tg_update_has_rules(this_tg);
> -		/* ignore root/second level */
> -		if (!cgroup_subsys_on_dfl(io_cgrp_subsys) || !blkg->parent ||
> -		    !blkg->parent->parent)
> -			continue;
> -	}
> +	blkg_for_each_descendant_pre(blkg, pos_css, tg_to_blkg(tg))
> +		tg_update_has_rules(blkg_to_tg(blkg));
>  	rcu_read_unlock();
>  
>  	/*
> @@ -1388,7 +1380,7 @@ static ssize_t tg_set_conf(struct kernfs_open_file *of,
>  	else
>  		*(unsigned int *)((void *)tg + of_cft(of)->private) = v;
>  
> -	tg_conf_updated(tg, false);
> +	tg_conf_updated(tg);
>  	ret = 0;
>  
>  unprep:
> @@ -1610,7 +1602,7 @@ static ssize_t tg_set_limit(struct kernfs_open_file *of,
>  	tg->iops[READ] = v[2];
>  	tg->iops[WRITE] = v[3];
>  
> -	tg_conf_updated(tg, false);
> +	tg_conf_updated(tg);
>  	ret = 0;
>  unprep:
>  	blkg_conf_unprep(&ctx);

Reviewed-by: Tao Cui <cuitao@xxxxxxxxxx>