linux-kernel - Re: [PATCH v5 20/27] cxl/extent: Process DCD events and realize region extents

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Message-ID: <20241030143232.000013b8@Huawei.com>
Date: Wed, 30 Oct 2024 14:32:32 +0000
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: <ira.weiny@...el.com>
CC: Dave Jiang <dave.jiang@...el.com>, Fan Ni <fan.ni@...sung.com>, "Navneet
 Singh" <navneet.singh@...el.com>, Jonathan Corbet <corbet@....net>, "Andrew
 Morton" <akpm@...ux-foundation.org>, Dan Williams <dan.j.williams@...el.com>,
	Davidlohr Bueso <dave@...olabs.net>, "Alison Schofield"
	<alison.schofield@...el.com>, Vishal Verma <vishal.l.verma@...el.com>,
	<linux-cxl@...r.kernel.org>, <linux-doc@...r.kernel.org>,
	<nvdimm@...ts.linux.dev>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 20/27] cxl/extent: Process DCD events and realize
 region extents

A few minor things inline from a fresh read.

Other than maybe a missing header, the others are all trivial
and you can make your own minds up.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...ei.com>

>  #endif /* __CXL_CORE_H__ */
> diff --git a/drivers/cxl/core/extent.c b/drivers/cxl/core/extent.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..315aa46252c15dcefe175da87522505f8ecf537c
> --- /dev/null
> +++ b/drivers/cxl/core/extent.c
> @@ -0,0 +1,372 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*  Copyright(c) 2024 Intel Corporation. All rights reserved. */
> +
> +#include <linux/device.h>
> +#include <cxl.h>


> +static bool extents_contain(struct cxl_dax_region *cxlr_dax,
> +			    struct cxl_endpoint_decoder *cxled,
> +			    struct range *new_range)
> +{
> +	struct match_data md = {
> +		.cxled = cxled,
> +		.new_range = new_range,
> +	};
> +
> +	struct device *extent_device __free(put_device)
> +			= device_find_child(&cxlr_dax->dev, &md, match_contains);
> +	if (!extent_device)
> +		return false;
> +
> +	return true;
trivial but could do.

	return extent_device != NULL;

> +}

> +static bool extents_overlap(struct cxl_dax_region *cxlr_dax,
> +			    struct cxl_endpoint_decoder *cxled,
> +			    struct range *new_range)
> +{
> +	struct match_data md = {
> +		.cxled = cxled,
> +		.new_range = new_range,
> +	};
> +
> +	struct device *extent_device __free(put_device)
> +			= device_find_child(&cxlr_dax->dev, &md, match_overlaps);
> +	if (!extent_device)
> +		return false;
> +
> +	return true;
As above.

> +}

> +static int cxlr_rm_extent(struct device *dev, void *data)
> +{
> +	struct region_extent *region_extent = to_region_extent(dev);
> +	struct range *region_hpa_range = data;
> +
> +	if (!region_extent)
> +		return 0;
> +
> +	/*
> +	 * Any extent which 'touches' the released range is removed.

Maybe single line comment syntax is fine here.

> +	 */
> +	if (range_overlaps(region_hpa_range, &region_extent->hpa_range)) {
> +		dev_dbg(dev, "Remove region extent HPA [range 0x%016llx-0x%016llx]\n",
> +			region_extent->hpa_range.start, region_extent->hpa_range.end);
> +		region_rm_extent(region_extent);
> +	}
> +	return 0;
> +}


> +/* Callers are expected to ensure cxled has been attached to a region */
> +int cxl_add_extent(struct cxl_memdev_state *mds, struct cxl_extent *extent)
> +{
> +	u64 start_dpa = le64_to_cpu(extent->start_dpa);
> +	struct cxl_memdev *cxlmd = mds->cxlds.cxlmd;
> +	struct cxl_endpoint_decoder *cxled;
> +	struct range ed_range, ext_range;
> +	struct cxl_dax_region *cxlr_dax;
> +	struct cxled_extent *ed_extent;
> +	struct cxl_region *cxlr;
> +	struct device *dev;
> +
> +	ext_range = (struct range) {
> +		.start = start_dpa,
> +		.end = start_dpa + le64_to_cpu(extent->length) - 1,
> +	};
> +
>


> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index 16e06b59d7f04762ca73a81740b0d6b2487301af..85b30a74a6fa5de1dd99c08c8318edd204e3e19d 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h

Is the xarray header included in here already?
If not it should be.

> @@ -506,6 +506,7 @@ static inline struct cxl_dev_state *mbox_to_cxlds(struct cxl_mailbox *cxl_mbox)
>   * @pmem_perf: performance data entry matched to PMEM partition
>   * @nr_dc_region: number of DC regions implemented in the memory device
>   * @dc_region: array containing info about the DC regions