On 11/15/25 2:34 AM, 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. Add the __data_racy annotation to request_queue.rq_timeout to suppress KCSAN data race reports about the rq_timeout reads.
This patch may cause a small delay in applying the new settings.
For all the attributes affected by this patch, I/O will complete correctly whether the old or the new value of the attribute is used.
This patch affects the following sysfs attributes:
- io_poll_delay
- io_timeout
- nomerges
- read_ahead_kb
- rq_affinity
Looks good to me: Reviewed-by: Nilay Shroff nilay@linux.ibm.com