On Wed, Jun 22, 2022 at 10:25:54AM +0200, Sebastian Andrzej Siewior wrote:

__blk_mq_delay_run_hw_queue() disables preemption to get a stable
current CPU number and then invokes __blk_mq_run_hw_queue() if the CPU
number is part the mask.

__blk_mq_run_hw_queue() acquires a spin_lock_t which is a sleeping lock
on PREEMPT_RT and can't be acquired with disabled preemption.

It is not required for correctness to invoke __blk_mq_run_hw_queue() on
a CPU matching hctx->cpumask. Both (async and direct requests) can run
on a CPU not matching hctx->cpumask.

The CPU mask without disabling preemption and invoking
__blk_mq_run_hw_queue().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

Looks fine:

Reviewed-by: Ming Lei <redacted>

Thanks,
Ming