From: Chengming Zhou zhouchengming@bytedance.com
[ Upstream commit e1dd7bc93029024af5688253b0c05181d6e01f8e ]
Although we don't need to realloc set->tags[] when shrink nr_hw_queues, we need to free them. Or these tags will be leaked.
How to reproduce: 1. mount -t configfs configfs /mnt 2. modprobe null_blk nr_devices=0 submit_queues=8 3. mkdir /mnt/nullb/nullb0 4. echo 1 > /mnt/nullb/nullb0/power 5. echo 4 > /mnt/nullb/nullb0/submit_queues 6. rmdir /mnt/nullb/nullb0
In step 4, will alloc 9 tags (8 submit queues and 1 poll queue), then in step 5, new_nr_hw_queues = 5 (4 submit queues and 1 poll queue). At last in step 6, only these 5 tags are freed, the other 4 tags leaked.
Signed-off-by: Chengming Zhou zhouchengming@bytedance.com Reviewed-by: Ming Lei ming.lei@redhat.com Link: https://lore.kernel.org/r/20230821095602.70742-1-chengming.zhou@linux.dev Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- block/blk-mq.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c index 953f08354c8c3..d9b365c2eaa0d 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -4402,9 +4402,13 @@ static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set, int new_nr_hw_queues) { struct blk_mq_tags **new_tags; + int i;
- if (set->nr_hw_queues >= new_nr_hw_queues) + if (set->nr_hw_queues >= new_nr_hw_queues) { + for (i = new_nr_hw_queues; i < set->nr_hw_queues; i++) + __blk_mq_free_map_and_rqs(set, i); goto done; + }
new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *), GFP_KERNEL, set->numa_node);