Documentation/block/ublk.rst

4 Userspace block device driver (ublk driver)
10 ublk is a generic framework for implementing block device logic from userspace.
11 The motivation behind it is that moving virtual block drivers into userspace,
16 Userspace block devices are attractive because:
29 on the device will be forwarded to ublk userspace program. For convenience,
30 in this document, ``ublk server`` refers to generic ublk userspace
31 program. ``ublksrv`` [#userspace]_ is one of such implementation. It
34 included, such as loop and null. Richard W.M. Jones wrote userspace nbd device
37 After the IO is handled by userspace, the result is committed back to the
39 logic is totally done by userspace, such as loop's IO handling, NBD's IO
50 implementation of userspace block device: not only IO request communication is
57 interface. Thus, ublk is generic userspace block device framework.
59 parameters from userspace.
64 ublk requires userspace ublk server to handle real block device logic.
118   After the server prepares userspace resources (such as creating per-queue
145   responsibility to save IO target specific info in userspace.
154   How to deal with userspace/kernel compatibility:
209   Requests which have not been issued to userspace are requeued. Requests
210   which have been issued to userspace are aborted.
214   requests which have been issued to userspace are requeued and will be
307 problem [#xiaoguang]_ Xiaoguang mentioned is that pages mapped to userspace
316 .. [#userspace] https://github.com/ming1/ubdsrv