usb: gadget: f_mass_storage: style corrections, cleanup & simplification

Fix spacing, improve error code returned, remove unused #define,
use strtobool() instead of kstrtou8().
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/f_mass_storage.c

@@ -3323,8 +3323,6 @@ static struct config_item_type fsg_lun_type = {
 	.ct_owner	= THIS_MODULE,
 };
 
-#define MAX_NAME_LEN	40
-
 static struct config_group *fsg_lun_make(struct config_group *group,
 					 const char *name)
 {
@@ -3348,7 +3346,8 @@ static struct config_group *fsg_lun_make(struct config_group *group,
 
 	fsg_opts = to_fsg_opts(&group->cg_item);
 	if (num >= FSG_MAX_LUNS)
-		return ERR_PTR(-ENODEV);
+		return ERR_PTR(-ERANGE);
+
 	mutex_lock(&fsg_opts->lock);
 	if (fsg_opts->refcnt || fsg_opts->common->luns[num]) {
 		ret = -EBUSY;
@@ -3364,7 +3363,6 @@ static struct config_group *fsg_lun_make(struct config_group *group,
 	memset(&config, 0, sizeof(config));
 	config.removable = true;
 
-
 	ret = fsg_common_create_lun(fsg_opts->common, &config, num, name,
 				    (const char **)&group->cg_item.ci_name);
 	if (ret) {
@@ -3438,22 +3436,23 @@ static ssize_t fsg_opts_stall_store(struct fsg_opts *opts, const char *page,
 				    size_t len)
 {
 	int ret;
-	u8 num;
+	bool stall;
 
 	mutex_lock(&opts->lock);
+
 	if (opts->refcnt) {
-		ret = -EBUSY;
-		goto end;
+		mutex_unlock(&opts->lock);
+		return -EBUSY;
 	}
-	ret = kstrtou8(page, 0, &num);
-	if (ret)
-		goto end;
 
-	opts->common->can_stall = num != 0;
+	ret = strtobool(page, &stall);
+	if (!ret) {
+		opts->common->can_stall = stall;
 		ret = len;
+	}
 
-end:
 	mutex_unlock(&opts->lock);
+
 	return ret;
 }