On Mon, Nov 10, 2025 at 08:24:18AM -0800, Bart Van Assche wrote:
Freezing the request queue from inside sysfs store callbacks may cause a deadlock in combination with the dm-multipath driver and the queue_if_no_path option. Additionally, freezing the request queue slows down system boot on systems where sysfs attributes are set synchronously.
Fix this by removing the blk_mq_freeze_queue() / blk_mq_unfreeze_queue() calls from the store callbacks that do not strictly need these callbacks. This patch may cause a small delay in applying the new settings.
This patch affects the following sysfs attributes:
- io_poll_delay
- io_timeout
- nomerges
- read_ahead_kb
- rq_affinity
I'd suggest to add words why freeze isn't needed, such as:
``` Intermediate value isn't possible, and either the old or new value is just fine to take in io fast path. ```
otherwise this patch is good for me.
Thanks, Ming