Hi,
在 2025/08/14 20:23, Nilay Shroff 写道:
On 8/14/25 9:05 AM, Yu Kuai wrote:
From: Yu Kuai <yukuai3@xxxxxxxxxx>
1) queue_requests_store() is the only caller of
blk_mq_update_nr_requests(), where queue is already freezed, no need to
check mq_freeze_depth;
2) q->tag_set must be set for request_based device, and queue_is_mq() is
already checked in blk_mq_queue_attr_visible(), no need to check
q->tag_set.
3) During initialization, hctx->tags in initialized before queue
kobject, and during del_gendisk, queue kobject is deleted before
exiting hctx, hence checking hctx->tags is useless.
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
block/blk-mq.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index b67d6c02eceb..3a219b7b3688 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -4921,24 +4921,15 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
{
struct blk_mq_tag_set *set = q->tag_set;
struct blk_mq_hw_ctx *hctx;
- int ret;
+ int ret = 0;
unsigned long i;
- if (WARN_ON_ONCE(!q->mq_freeze_depth))
- return -EINVAL;
-
- if (!set)
- return -EINVAL;
-
if (q->nr_requests == nr)
return 0;
blk_mq_quiesce_queue(q);
- ret = 0;
queue_for_each_hw_ctx(q, hctx, i) {
- if (!hctx->tags)
- continue;
It's possible that hctx->tags is set to NULL in case no software
queues are mapped to the hardware queue. So it seems that this
check is valid. Please see blk_mq_map_swqueue().
Ok, thanks for the reviw.
I didn't notice this, just wonder how can this happen?
nr_hw_queues > NR_CPUS?
Thanks,
Kuai
Thanks,
--Nilay
.
