Re: [PATCH 04/10] block: use queue_limits_commit_update in queue_attr_store

[Damien Le Moal <dlemoal@kernel.org>]

On 1/6/25 7:06 PM, Christoph Hellwig wrote:
> Use queue_limits_commit_update to apply a consistent freeze vs limits
> lock order in queue_attr_store.  Also remove taking the sysfs lock
> as it doesn't protect anything here.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Oops. OK. so please disregard my comments on patch 3. This is all fixed here.
May be sqash this patch with patch 3 ?

> ---
>  block/blk-sysfs.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 
> diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
> index 8d69315e986d..3bac27fcd635 100644
> --- a/block/blk-sysfs.c
> +++ b/block/blk-sysfs.c
> @@ -687,22 +687,24 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
>  	if (entry->load_module)
>  		entry->load_module(disk, page, length);
>  
> -	mutex_lock(&q->sysfs_lock);
> -	blk_mq_freeze_queue(q);
>  	if (entry->store_limit) {
>  		struct queue_limits lim = queue_limits_start_update(q);
>  
>  		res = entry->store_limit(disk, page, length, &lim);
>  		if (res < 0) {
>  			queue_limits_cancel_update(q);
> -		} else {
> -			res = queue_limits_commit_update(q, &lim);
> -			if (!res)
> -				res = length;
> +			return res;
>  		}
> -	} else {
> -		res = entry->store(disk, page, length);
> +
> +		res = queue_limits_commit_update_frozen(q, &lim);
> +		if (res)
> +			return res;
> +		return length;
>  	}
> +
> +	mutex_lock(&q->sysfs_lock);
> +	blk_mq_freeze_queue(q);
> +	res = entry->store(disk, page, length);
>  	blk_mq_unfreeze_queue(q);
>  	mutex_unlock(&q->sysfs_lock);
>  	return res;


-- 
Damien Le Moal
Western Digital Research