Hello maintainers, I'm trying to explore and test IO polling behavior of block devices in my system, NVMe drives to be specific. Upon trying, I noticed the legacy /sys/block/<disk>/queue/io_poll no longer changes the polling behavior of the device correctly. I found out the change from a614dd228035 block: don't allow writing to the poll queue attribute (https://lore.kernel.org/all/20211012111226.760968-16-hch@xxxxxx/) The dmesg prompts user to use driver specific parameters, but for this case, I can not find, either from code or documentation, parameter from the nvme driver to set polling behavior for the drive similar to the legacy io_poll sysfs interface. I realized I can use flags from either io_uring or the nvme passthrough commands to specify polling behavior. But are there still some configs I can make to change the entire drive's IO to polling, so that legacy applications not using io_uring can still have it? Upon reading the entire patch set, it feels to me that since we are changing the polling control to a per-bio flag, is drive-wide control of polling behavior just straight-out impossible now? Moreover, the block layer documentation at Documentation/ABI/stable/sysfs-block still documents the legacy behavior of the io_poll sysfs file. This is confusing for users trying to figure out reason of the failed or unexpected behavior after writing to the file and seeing the dmesg, particularly because there are many articles on the Internet describing the legacy behavior. If the maintainers agree, I can help update these documentations. Thanks a lot for your kind help! Teng Qin
