Re: [PATCH v2 21/28] cxl/region: Enable the assignment of endpoint decoders to regions

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Thu, 14 Jul 2022 17:02:41 -0700
Dan Williams <dan.j.williams@intel.com> wrote:

> The region provisioning process involves allocating DPA to a set of
> endpoint decoders, and HPA plus the region geometry to a region device.
> Then the decoder is assigned to the region. At this point several
> validation steps can be performed to validate that the decoder is
> suitable to participate in the region.
> 
> Co-developed-by: Ben Widawsky <bwidawsk@kernel.org>
> Signed-off-by: Ben Widawsky <bwidawsk@kernel.org>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

I think you've lost some planned changes here as typos from v1 review
still here as is the stale comment.

With those fixed
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>


 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index b1e847827c6b..871bfdbb9bc8 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c

> +/*
> + * - Check that the given endpoint is attached to a host-bridge identified
> + *   in the root interleave.

In reply to v1 review I think you said you had dropped this comment as stale?

> + */
> +static int cxl_region_attach(struct cxl_region *cxlr,
> +			     struct cxl_endpoint_decoder *cxled, int pos)
> +{
> +	struct cxl_region_params *p = &cxlr->params;
> +
> +	if (cxled->mode == CXL_DECODER_DEAD) {
> +		dev_dbg(&cxlr->dev, "%s dead\n", dev_name(&cxled->cxld.dev));
> +		return -ENODEV;
> +	}
> +
> +	if (pos >= p->interleave_ways) {
> +		dev_dbg(&cxlr->dev, "position %d out of range %d\n", pos,
> +			p->interleave_ways);
> +		return -ENXIO;
> +	}
> +
> +	if (p->targets[pos] == cxled)
> +		return 0;
> +
> +	if (p->targets[pos]) {
> +		struct cxl_endpoint_decoder *cxled_target = p->targets[pos];
> +		struct cxl_memdev *cxlmd_target = cxled_to_memdev(cxled_target);
> +
> +		dev_dbg(&cxlr->dev, "position %d already assigned to %s:%s\n",
> +			pos, dev_name(&cxlmd_target->dev),
> +			dev_name(&cxled_target->cxld.dev));
> +		return -EBUSY;
> +	}
> +
> +	p->targets[pos] = cxled;
> +	cxled->pos = pos;
> +	p->nr_targets++;
> +
> +	return 0;
> +}
> +
> +static void cxl_region_detach(struct cxl_endpoint_decoder *cxled)
> +{
> +	struct cxl_region *cxlr = cxled->cxld.region;
> +	struct cxl_region_params *p;
> +
> +	lockdep_assert_held_write(&cxl_region_rwsem);
> +
> +	if (!cxlr)
> +		return;
> +
> +	p = &cxlr->params;
> +	get_device(&cxlr->dev);
> +
> +	if (cxled->pos < 0 || cxled->pos >= p->interleave_ways ||
> +	    p->targets[cxled->pos] != cxled) {
> +		struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);
> +
> +		dev_WARN_ONCE(&cxlr->dev, 1, "expected %s:%s at position %d\n",
> +			      dev_name(&cxlmd->dev), dev_name(&cxled->cxld.dev),
> +			      cxled->pos);
> +		goto out;
> +	}
> +
> +	p->targets[cxled->pos] = NULL;
> +	p->nr_targets--;
> +
> +	/* notify the region driver that one of its targets has deparated */
typo still here.

> +	up_write(&cxl_region_rwsem);
> +	device_release_driver(&cxlr->dev);
> +	down_write(&cxl_region_rwsem);
> +out:
> +	put_device(&cxlr->dev);
> +}