cxl/region: Factor out code to find a root decoder's region

In function cxl_add_to_region() there is code to determine a root
decoder's region. Factor that code out. This is in preparation to
further rework and simplify function cxl_add_to_region().

The reference count must be decremented after using the region.
cxl_find_region_by_range() is paired with the put_cxl_region cleanup
helper that can be used for this.

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

Signed-off-by: Robert Richter <rrichter@amd.com>
Reviewed-by: Gregory Price <gourry@gourry.net>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: "Fabio M. De Francesco" <fabio.m.de.francesco@linux.intel.com>
Tested-by: Gregory Price <gourry@gourry.net>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Link: https://patch.msgid.link/20250509150700.2817697-11-rrichter@amd.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index e76f1cf2e7909f5a7d6ec4b5fb1349f867fbc475..7def1c20b5f2b347c755d287b92b56914c02ccf4 100644 (file)
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3405,12 +3405,23 @@ static struct cxl_region *construct_region(struct cxl_root_decoder *cxlrd,
        return cxlr;
 }
 
+static struct cxl_region *
+cxl_find_region_by_range(struct cxl_root_decoder *cxlrd, struct range *hpa)
+{
+       struct device *region_dev;
+
+       region_dev = device_find_child(&cxlrd->cxlsd.cxld.dev, hpa,
+                                      match_region_by_range);
+       if (!region_dev)
+               return NULL;
+
+       return to_cxl_region(region_dev);
+}
+
 int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)
 {
        struct range *hpa = &cxled->cxld.hpa_range;
-       struct device *region_dev;
        struct cxl_region_params *p;
-       struct cxl_region *cxlr;
        bool attach = false;
        int rc;
 
@@ -3424,13 +3435,10 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)
         * one does the construction and the others add to that.
         */
        mutex_lock(&cxlrd->range_lock);
-       region_dev = device_find_child(&cxlrd->cxlsd.cxld.dev, hpa,
-                                      match_region_by_range);
-       if (!region_dev) {
+       struct cxl_region *cxlr __free(put_cxl_region) =
+               cxl_find_region_by_range(cxlrd, hpa);
+       if (!cxlr)
                cxlr = construct_region(cxlrd, cxled);
-               region_dev = &cxlr->dev;
-       } else
-               cxlr = to_cxl_region(region_dev);
        mutex_unlock(&cxlrd->range_lock);
 
        rc = PTR_ERR_OR_ZERO(cxlr);
@@ -3455,8 +3463,6 @@ int cxl_add_to_region(struct cxl_endpoint_decoder *cxled)
                                p->res);
        }
 
-       put_device(region_dev);
-
        return rc;
 }
 EXPORT_SYMBOL_NS_GPL(cxl_add_to_region, "CXL");

diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 371f9dcfb61a9dc076f936ac43a369d577f915a0..ba08b77b65da3d8fe9de0f1384c77ec84ed205d5 100644 (file)
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -741,6 +741,7 @@ 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))
+DEFINE_FREE(put_cxl_region, struct cxl_region *, if (!IS_ERR_OR_NULL(_T)) put_device(&_T->dev))
 
 int devm_cxl_enumerate_ports(struct cxl_memdev *cxlmd);
 void cxl_bus_rescan(void);