Re: [PATCH] drivers/nvme/host/pci: Fix the asynchronous detection issue of nvme devices

[Damien Le Moal]

On 7/25/25 01:07, Bart Van Assche wrote:
> On 7/20/25 11:51 AM, likunyu10 wrote:
>> PROBE_PREFER_ASYNCHRONOUS asynchronous detection has a significant impact
>> on important devices. For example, if a server has two or more nvme disk
>> devices, it can cause disk loading disorder, which can also have a
>> certain impact on actual production environments.
> 
> That's intentional. Please fix your user space code that uses hard-coded
> NVMe block device names or introduce a mechanism in user space for block
> devices that is similar to the predictable network interface names
> mechanism. See also https://systemd.io/PREDICTABLE_INTERFACE_NAMES/.

Userspace can use /dev/disk/by-id or any of the other /dev/disk/by-* for
reliable device names. Using directly /dev/sd* or /dev/nvme* is bad userspace
practice.

Even without asynchronous device scan, adding or removing a device to a system
can change device file names. The symlinks in /dev/disk/by-id are stable and
will exist as long as a device is present.


-- 
Damien Le Moal
Western Digital Research