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

[Stephen Bates]

On Tue, Sep 27, 2016 at 05:17:04PM -0600, Jon Derrick wrote:
> Hi Stephen,
>
> Thanks for reviving the CMB discussions. Everything seems reasonable to
> me, but I must question if we want a 'show' without a 'control'.
> Consider if the 'control' ends up requiring an API that supercedes the
> 'show' in a more natural way.
>
> Otherwise I'm for this.

Great.

>
> >  	}
> >
> > -	if (readl(dev->bar + NVME_REG_VS) >= NVME_VS(1, 2))
> > +	/*
> > +	 * CMBs can currently only exist on >=1.2 PCIe devices. We only
> > +	 * populate sysfs if a CMB is implemented. Note that we add the
> > +	 * CMB attribute to the nvme_ctrl kobj which removes the need to remove
> > +	 * it on exit. Since nvme_dev_attrs_group has no name we can pass
> > +	 * NULL as final argument to sysfs_add_file_to_group.
> > +	 */
> > +
> > +	if (readl(dev->bar + NVME_REG_VS) >= NVME_VS(1, 2)) {
> >  		dev->cmb = nvme_map_cmb(dev);
> >
> > +		if (readl(dev->bar + NVME_REG_CMBSZ)) {
> Small nit: we have this value cached in dev->cmbsz. So unless something
> has changed in the configuration, we could use that instead.

Good point. I will await other feedback and then issue a v1 with this
change. Can I add a Reviewed-by tag from you?

Cheers

Stephen