Re: [PATCH v3 4/7] block: free both map and request

[Bart Van Assche <bvanassche@xxxxxxx>]

On 4/6/20 12:36 PM, Weiping Zhang wrote:
> For this error handle, it should free both map and request,
> otherwise memleak occur.
            ^^^^^^^
Please expand this into "a memory leak".

> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 4692e8232699..406df9ce9b55 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -2990,7 +2990,7 @@ static int __blk_mq_alloc_rq_map_and_requests(struct blk_mq_tag_set *set)
>   
>   out_unwind:
>   	while (--i >= 0)
> -		blk_mq_free_rq_map(set->tags[i]);
> +		blk_mq_free_map_and_requests(set, i);
>   
>   	return -ENOMEM;
>   }

The current upstream implementation is as follows:

static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
{
	int i;

	for (i = 0; i < set->nr_hw_queues; i++)
		if (!__blk_mq_alloc_rq_map(set, i))
			goto out_unwind;

	return 0;

out_unwind:
	while (--i >= 0)
		blk_mq_free_rq_map(set->tags[i]);

	return -ENOMEM;
}

The pointers to the memory allocated by __blk_mq_alloc_rq_map() are 
stored in set->tags[i] and set->tags[i]->static_rqs. 
blk_mq_free_rq_map() frees set->tags[i]->static_rqs and set->tags[i]. In 
other words, I don't see which memory is leaked. What did I miss?

Thanks,

Bart.