Commit 9466ee98 authored by Robert Richter's avatar Robert Richter Committed by Dave Jiang
Browse files

cxl/region: Factor out code to find the root decoder 



In function cxl_add_to_region() there is code to determine the root
decoder associated to an endpoint decoder. Factor out that code for
later reuse. This has the benefit of reducing cxl_add_to_region()'s
function complexity.

The reference count must be decremented after using the root decoder.
cxl_find_root_decoder() is paired with the put_cxl_root_decoder
cleanup helper that can be used for this.

[dj: Fixed up "obj __free(...) = NULL" pattern]

Signed-off-by: default avatarRobert Richter <rrichter@amd.com>
Reviewed-by: default avatarGregory Price <gourry@gourry.net>
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: default avatarDave Jiang <dave.jiang@intel.com>
Reviewed-by: default avatarDan Williams <dan.j.williams@intel.com>
Reviewed-by: default avatarAlison Schofield <alison.schofield@intel.com>
Reviewed-by: default avatar"Fabio M. De Francesco" <fabio.m.de.francesco@linux.intel.com>
Tested-by: default avatarGregory Price <gourry@gourry.net>
Acked-by: default avatarDan Williams <dan.j.williams@intel.com>
Link: https://patch.msgid.link/20250509150700.2817697-10-rrichter@amd.com


Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
parent 74bf125a

drivers/cxl/core/region.c

+29 −19
Original line number Diff line number Diff line
@@ -3216,6 +3216,29 @@ static int match_root_decoder_by_range(struct device *dev, 
	return range_contains(r1, r2);

}



static struct cxl_root_decoder *

cxl_find_root_decoder(struct cxl_endpoint_decoder *cxled)

{

	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);

	struct cxl_port *port = cxled_to_port(cxled);

	struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port);

	struct cxl_decoder *cxld = &cxled->cxld;

	struct range *hpa = &cxld->hpa_range;

	struct device *cxlrd_dev;



	cxlrd_dev = device_find_child(&cxl_root->port.dev, hpa,

				      match_root_decoder_by_range);

	if (!cxlrd_dev) {

		dev_err(cxlmd->dev.parent,

			"%s:%s no CXL window for range %#llx:%#llx\n",

			dev_name(&cxlmd->dev), dev_name(&cxld->dev),

			cxld->hpa_range.start, cxld->hpa_range.end);

		return NULL;

	}



	return to_cxl_root_decoder(cxlrd_dev);

}



static int match_region_by_range(struct device *dev, const void *data)

{

	struct cxl_region_params *p;
@@ -3384,29 +3407,17 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd, 


int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)

{

	struct cxl_memdev *cxlmd = cxled_to_memdev(cxled);

	struct cxl_port *port = cxled_to_port(cxled);

	struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port);

	struct range *hpa = &cxled->cxld.hpa_range;

	struct cxl_decoder *cxld = &cxled->cxld;

	struct device *cxlrd_dev, *region_dev;

	struct cxl_root_decoder *cxlrd;

	struct device *region_dev;

	struct cxl_region_params *p;

	struct cxl_region *cxlr;

	bool attach = false;

	int rc;



	cxlrd_dev = device_find_child(&cxl_root->port.dev, &cxld->hpa_range,

				      match_root_decoder_by_range);

	if (!cxlrd_dev) {

		dev_err(cxlmd->dev.parent,

			"%s:%s no CXL window for range %#llx:%#llx\n",

			dev_name(&cxlmd->dev), dev_name(&cxld->dev),

			cxld->hpa_range.start, cxld->hpa_range.end);

	struct cxl_root_decoder *cxlrd __free(put_cxl_root_decoder) =

		cxl_find_root_decoder(cxled);

	if (!cxlrd)

		return -ENXIO;

	}



	cxlrd = to_cxl_root_decoder(cxlrd_dev);



	/*

	 * Ensure that if multiple threads race to construct_region() for @hpa
@@ -3424,7 +3435,7 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled) 


	rc = PTR_ERR_OR_ZERO(cxlr);

	if (rc)

		goto out;

		return rc;



	attach_target(cxlr, cxled, -1, TASK_UNINTERRUPTIBLE);
@@ -3445,8 +3456,7 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled) 
	}



	put_device(region_dev);

out:

	put_device(cxlrd_dev);



	return rc;

}

EXPORT_SYMBOL_NS_GPL(cxl_add_to_region, "CXL");

drivers/cxl/cxl.h

+1 −0
Original line number Diff line number Diff line
@@ -740,6 +740,7 @@ struct cxl_root *find_cxl_root(struct cxl_port *port); 


DEFINE_FREE(put_cxl_root, struct cxl_root *, if (_T) put_device(&_T->port.dev))

DEFINE_FREE(put_cxl_port, struct cxl_port *, if (!IS_ERR_OR_NULL(_T)) put_device(&_T->dev))

DEFINE_FREE(put_cxl_root_decoder, struct cxl_root_decoder *, if (!IS_ERR_OR_NULL(_T)) put_device(&_T->cxlsd.cxld.dev))



int devm_cxl_enumerate_ports(struct cxl_memdev *cxlmd);

void cxl_bus_rescan(void);