Messages in this thread Patch in this message | | | From | Yu Kuai <> | Subject | [PATCH -next] blk-iocost: fix sleeping in atomic warning for wbt_enable_default() | Date | Wed, 8 Feb 2023 11:48:03 +0800 |
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From: Yu Kuai <yukuai3@huawei.com>
There are following smatch warning:
block/blk-wbt.c:843 wbt_init() warn: sleeping in atomic context ioc_qos_write() <- disables preempt -> wbt_enable_default() -> wbt_init()
wbt_init() will be called from wbt_enable_default() if wbt is not initialized, currently wbt is initialized in blk_register_queue(), hence wbt_init() will never be called from iocost and this warning is false positive.
However, we might support rq_qos destruction dynamically in the future, and it's better to prevent that, hence move wbt_enable_default() outside 'ioc->lock'. This is safe because queue is still freezed.
Reported-by: Dan Carpenter <error27@gmail.com> Link: https://lore.kernel.org/lkml/Y+Ja5SRs886CEz7a@kadam/ Signed-off-by: Yu Kuai <yukuai3@huawei.com> --- block/blk-iocost.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 7a2dc9dc8e3b..03bfe1dda07c 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -3279,11 +3279,9 @@ static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input, blk_stat_enable_accounting(disk->queue); blk_queue_flag_set(QUEUE_FLAG_RQ_ALLOC_TIME, disk->queue); ioc->enabled = true; - wbt_disable_default(disk); } else { blk_queue_flag_clear(QUEUE_FLAG_RQ_ALLOC_TIME, disk->queue); ioc->enabled = false; - wbt_enable_default(disk); } if (user) { @@ -3296,6 +3294,10 @@ static ssize_t ioc_qos_write(struct kernfs_open_file *of, char *input, ioc_refresh_params(ioc, true); spin_unlock_irq(&ioc->lock); + if (enable) + wbt_disable_default(disk); + else + wbt_enable_default(disk); blk_mq_unquiesce_queue(disk->queue); blk_mq_unfreeze_queue(disk->queue); -- 2.31.1
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