testing: nvdimm: make struct class structures constant

Now that the driver core allows for struct class to be in read-only
memory, we should make all 'class' structures declared at build time
placing them into read-only memory, instead of having to be dynamically
allocated at runtime.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Tested-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/2023100611-platinum-galleria-ceb3@gregkhSigned-off-by: Ira Weiny <ira.weiny@intel.com>

tools/testing/nvdimm/test/ndtest.c

@@ -38,7 +38,11 @@ enum {
 
 static DEFINE_SPINLOCK(ndtest_lock);
 static struct ndtest_priv *instances[NUM_INSTANCES];
-static struct class *ndtest_dimm_class;
+
+static const struct class ndtest_dimm_class = {
+	.name = "nfit_test_dimm",
+};
+
 static struct gen_pool *ndtest_pool;
 
 static struct ndtest_dimm dimm_group1[] = {
@@ -737,7 +741,7 @@ static int ndtest_dimm_register(struct ndtest_priv *priv,
 		return -ENXIO;
 	}
 
-	dimm->dev = device_create_with_groups(ndtest_dimm_class,
+	dimm->dev = device_create_with_groups(&ndtest_dimm_class,
 					     &priv->pdev.dev,
 					     0, dimm, dimm_attribute_groups,
 					     "test_dimm%d", id);
@@ -906,8 +910,7 @@ static void cleanup_devices(void)
 		gen_pool_destroy(ndtest_pool);
 
 
-	if (ndtest_dimm_class)
-		class_destroy(ndtest_dimm_class);
+	class_unregister(&ndtest_dimm_class);
 }
 
 static __init int ndtest_init(void)
@@ -921,11 +924,9 @@ static __init int ndtest_init(void)
 
 	nfit_test_setup(ndtest_resource_lookup, NULL);
 
-	ndtest_dimm_class = class_create("nfit_test_dimm");
-	if (IS_ERR(ndtest_dimm_class)) {
-		rc = PTR_ERR(ndtest_dimm_class);
+	rc = class_regster(&ndtest_dimm_class);
+	if (rc)
 		goto err_register;
-	}
 
 	ndtest_pool = gen_pool_create(ilog2(SZ_4M), NUMA_NO_NODE);
 	if (!ndtest_pool) {

tools/testing/nvdimm/test/nfit.c

@@ -1712,7 +1712,9 @@ static void put_dimms(void *data)
 			device_unregister(t->dimm_dev[i]);
 }
 
-static struct class *nfit_test_dimm;
+static const struct class nfit_test_dimm = {
+	.name = "nfit_test_dimm",
+};
 
 static int dimm_name_to_id(struct device *dev)
 {
@@ -1830,7 +1832,7 @@ static int nfit_test_dimm_init(struct nfit_test *t)
 	if (devm_add_action_or_reset(&t->pdev.dev, put_dimms, t))
 		return -ENOMEM;
 	for (i = 0; i < t->num_dcr; i++) {
-		t->dimm_dev[i] = device_create_with_groups(nfit_test_dimm,
+		t->dimm_dev[i] = device_create_with_groups(&nfit_test_dimm,
 				&t->pdev.dev, 0, NULL,
 				nfit_test_dimm_attribute_groups,
 				"test_dimm%d", i + t->dcr_idx);
@@ -3276,11 +3278,9 @@ static __init int nfit_test_init(void)
 	if (!nfit_wq)
 		return -ENOMEM;
 
-	nfit_test_dimm = class_create("nfit_test_dimm");
-	if (IS_ERR(nfit_test_dimm)) {
-		rc = PTR_ERR(nfit_test_dimm);
+	rc = class_register(&nfit_test_dimm);
+	if (rc)
 		goto err_register;
-	}
 
 	nfit_pool = gen_pool_create(ilog2(SZ_4M), NUMA_NO_NODE);
 	if (!nfit_pool) {
@@ -3377,7 +3377,7 @@ static __exit void nfit_test_exit(void)
 
 	for (i = 0; i < NUM_NFITS; i++)
 		put_device(&instances[i]->pdev.dev);
-	class_destroy(nfit_test_dimm);
+	class_unregister(&nfit_test_dimm);
 }
 
 module_init(nfit_test_init);