[dm-devel] dm-mq and end_clone_request()

[Bart Van Assche]

On 07/27/2016 08:52 AM, Benjamin Marzinski wrote:
> if you look in drivers/md/dm-ioctl.c at do_resume(), device mapper
> internally does a suspend when you call resume with a new table loaded.
> That's when these suspends are happening.
>
> In the userspace tools, this happens in the DM_DEVICE_RESUME calls after
> dm_addmap_reload(), which loads the new table.  These all happen in the
> domap() function.

Thanks Ben for chiming in. As far as I can see md->map is only used in 
the I/O submission path but not in the I/O completion path. So why to 
suspend and resume I/O before activating the new map? Do you think it 
would be safe to activate the new map without suspending and resuming I/O?

Thanks,

Bart.