Re: [PATCH 4/8] blk-mq: Facilitate a shared sbitmap per tagset

[John Garry <john.garry@xxxxxxxxxx>]

> +		blk_mq_free_tags(tags);
>   }
>   
>   struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
>   					unsigned int hctx_idx,
>   					unsigned int nr_tags,
> -					unsigned int reserved_tags)
> +					unsigned int reserved_tags,
> +					bool shared_tags)
>   {
>   	struct blk_mq_tags *tags;
>   	int node;
> @@ -2096,8 +2098,9 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
>   	if (node == NUMA_NO_NODE)
>   		node = set->numa_node;
>   
> -	tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
> -				BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
> +	tags = blk_mq_init_tags(set, nr_tags, reserved_tags, node,
> +				BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags),
> +				shared_tags);
>   	if (!tags)
>   		return NULL;
>   
> @@ -2105,7 +2108,8 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
>   				 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
>   				 node);
>   	if (!tags->rqs) {
> -		blk_mq_free_tags(tags);
> +		if (!blk_mq_is_sbitmap_shared(set))
> +			blk_mq_free_tags(tags);

Don't we still need to free the tags memory but not have the 
blk_mq_free_tags()->sbitmap_queue_free() calls in case of shared tags?

>   		return NULL;
>   	}
>   
> @@ -2114,7 +2118,8 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
>   					node);
>   	if (!tags->static_rqs) {
>   		kfree(tags->rqs);
> -		blk_mq_free_tags(tags);
> +		if (!blk_mq_is_sbitmap_shared(set))
> +			blk_mq_free_tags(tags);
>   		return NULL;
>   	}