nvmem: core: remove global nvmem_cells_group

nvmem_cells_groups is a global variable that is also mutated.
This is complicated and error-prone.

Instead use a normal stack variable.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20240705074852.423202-11-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: t-8ch

drivers/nvmem/core.c

@@ -357,11 +357,6 @@ static const struct attribute_group nvmem_bin_group = {
 	.is_bin_visible = nvmem_bin_attr_is_visible,
 };
 
-/* Cell attributes will be dynamically allocated */
-static struct attribute_group nvmem_cells_group = {
-	.name		= "cells",
-};
-
 static const struct attribute_group *nvmem_dev_groups[] = {
 	&nvmem_bin_group,
 	NULL,
@@ -424,23 +419,24 @@ static void nvmem_sysfs_remove_compat(struct nvmem_device *nvmem,
 
 static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem)
 {
-	struct bin_attribute **cells_attrs, *attrs;
+	struct attribute_group group = {
+		.name	= "cells",
+	};
 	struct nvmem_cell_entry *entry;
+	struct bin_attribute *attrs;
 	unsigned int ncells = 0, i = 0;
 	int ret = 0;
 
 	mutex_lock(&nvmem_mutex);
 
-	if (list_empty(&nvmem->cells) || nvmem->sysfs_cells_populated) {
-		nvmem_cells_group.bin_attrs = NULL;
+	if (list_empty(&nvmem->cells) || nvmem->sysfs_cells_populated)
 		goto unlock_mutex;
-	}
 
 	/* Allocate an array of attributes with a sentinel */
 	ncells = list_count_nodes(&nvmem->cells);
-	cells_attrs = devm_kcalloc(&nvmem->dev, ncells + 1,
-				   sizeof(struct bin_attribute *), GFP_KERNEL);
-	if (!cells_attrs) {
+	group.bin_attrs = devm_kcalloc(&nvmem->dev, ncells + 1,
+				       sizeof(struct bin_attribute *), GFP_KERNEL);
+	if (!group.bin_attrs) {
 		ret = -ENOMEM;
 		goto unlock_mutex;
 	}
@@ -467,13 +463,11 @@ static int nvmem_populate_sysfs_cells(struct nvmem_device *nvmem)
 			goto unlock_mutex;
 		}
 
-		cells_attrs[i] = &attrs[i];
+		group.bin_attrs[i] = &attrs[i];
 		i++;
 	}
 
-	nvmem_cells_group.bin_attrs = cells_attrs;
-
-	ret = device_add_group(&nvmem->dev, &nvmem_cells_group);
+	ret = device_add_group(&nvmem->dev, &group);
 	if (ret)
 		goto unlock_mutex;