[PATCH 1/1] nvme : Add sysfs entry for NVMe CMBs when appropriate

[Sagi Grimberg]

> Add a sysfs attribute that contains salient information about the NVMe
> Controller Memory Buffer when one is present. For now, just display the
> information about the CMB available from the control registers. We attach
> the CMB attribute file to the existing nvme_ctrl sysfs group so it can
> handle the sysfs teardown.

Hey Stephen,

I'm wandering if placing this only for pci is correct. In theory, we
could have fabrics expose a cmb (while its usage is still somewhat
unknown at the moment).

Perhaps cmbloc/cmbsize should exist in ctrl and be queried by
->reg_read32() callout. In addition, we would need a new map_cmb()
callout in ctrl->ops.

Thoughts?