Revert "target: Do not special-case loop and iscsi fabric module loads"

Existing lio_dump.py code expects this to be in place for /iscsi.

Revert for now to avoid userspace breakage in lio-utils

This reverts commit fd88a785f9ac5d6be437c528571ccd85cdf2d493.
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_configfs.c

@@ -122,9 +122,47 @@ static struct config_group *target_core_register_fabric(
 	const char *name)
 {
 	struct target_fabric_configfs *tf;
+	int ret;
 
 	pr_debug("Target_Core_ConfigFS: REGISTER -> group: %p name:"
 			" %s\n", group, name);
+	/*
+	 * Below are some hardcoded request_module() calls to automatically
+	 * local fabric modules when the following is called:
+	 *
+	 * mkdir -p /sys/kernel/config/target/$MODULE_NAME
+	 *
+	 * Note that this does not limit which TCM fabric module can be
+	 * registered, but simply provids auto loading logic for modules with
+	 * mkdir(2) system calls with known TCM fabric modules.
+	 */
+	if (!strncmp(name, "iscsi", 5)) {
+		/*
+		 * Automatically load the LIO Target fabric module when the
+		 * following is called:
+		 *
+		 * mkdir -p $CONFIGFS/target/iscsi
+		 */
+		ret = request_module("iscsi_target_mod");
+		if (ret < 0) {
+			pr_err("request_module() failed for"
+				" iscsi_target_mod.ko: %d\n", ret);
+			return ERR_PTR(-EINVAL);
+		}
+	} else if (!strncmp(name, "loopback", 8)) {
+		/*
+		 * Automatically load the tcm_loop fabric module when the
+		 * following is called:
+		 *
+		 * mkdir -p $CONFIGFS/target/loopback
+		 */
+		ret = request_module("tcm_loop");
+		if (ret < 0) {
+			pr_err("request_module() failed for"
+				" tcm_loop.ko: %d\n", ret);
+			return ERR_PTR(-EINVAL);
+		}
+	}
 
 	tf = target_core_get_fabric(name);
 	if (!tf) {