Backend Interface#

The core of the xNVMe API is encapsulated by a backend interface. The backend interface consists of implementations of the following.

Attributes#

  • name, name of the backend

  • schemes, array of supported prefixes e.g. file

  • nschemes, number of schemes

  • enabled, property indicating whether the backend-support is compiled in

Device#

  • enumerate(), lists devices

  • dev_from_ident(), open of a given device and return a handle

  • dev_close(), close a device handle

Memory#

  • buf_alloc(), allocate buffer usable with commands

  • buf_free(), de-allocate buffers

  • buf_vtophys()

  • buf_realloc()

Asynchronous#

  • cmd_io(), submit an IO-command to a qpair

  • poke(), process completions on a qpair

  • wait(), wait until all outstanding commands are completed

  • init(), initialize a qpair

  • term(), terminate a qpair

  • supported(), informed whether async. commands are supported

Synchronous#

  • cmd_io(), submit an IO-command and wait for its completion

  • cmd_admin(), submit and Admin-command and wait for its completion

  • supported(), inform wether sync. commands are supported

Backend Interface - Implementation#

If you want to add a backend for e.g. Windows 10, you could add the implementation in src/xnvme_be_win10.c and then it to the backend registry in include/xnvme_be_registry.h and src/xnvme_be.c.

Have a look at the existing backend-implementations:

  • xnvme_be.c

  • xnvme_be_*.c

  • include/xnvme_be_registry.h

And the definition of the backend-interface in:

  • include/xnvme_be.h

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