From fae7cb03d3dce923679fc72da3d94e87f850975c Mon Sep 17 00:00:00 2001
From: mav <mav@FreeBSD.org>
Date: Tue, 7 Feb 2017 01:55:48 +0000
Subject: MFC r312603: Add initial support for CTL module unloading.

It is only a first step and not perfect, but better then nothing.
The main blocker is CAM target frontend, that can not be unloaded,
since CAM does not have mechanism to unregister periph driver now.
---
 sys/cam/ctl/ctl_backend.c | 73 ++++++++++++++++-------------------------------
 1 file changed, 24 insertions(+), 49 deletions(-)

(limited to 'sys/cam/ctl/ctl_backend.c')

diff --git a/sys/cam/ctl/ctl_backend.c b/sys/cam/ctl/ctl_backend.c
index 86f7d3c..bac7e85 100644
--- a/sys/cam/ctl/ctl_backend.c
+++ b/sys/cam/ctl/ctl_backend.c
@@ -67,11 +67,10 @@ ctl_backend_register(struct ctl_backend_driver *be)
 {
 	struct ctl_softc *softc = control_softc;
 	struct ctl_backend_driver *be_tmp;
+	int error;
 
+	/* Sanity check, make sure this isn't a duplicate registration. */
 	mtx_lock(&softc->ctl_lock);
-	/*
-	 * Sanity check, make sure this isn't a duplicate registration.
-	 */
 	STAILQ_FOREACH(be_tmp, &softc->be_list, links) {
 		if (strcmp(be_tmp->name, be->name) == 0) {
 			mtx_unlock(&softc->ctl_lock);
@@ -79,39 +78,24 @@ ctl_backend_register(struct ctl_backend_driver *be)
 		}
 	}
 	mtx_unlock(&softc->ctl_lock);
-
-	/*
-	 * Call the backend's initialization routine.
-	 */
-	be->init();
-
-	mtx_lock(&softc->ctl_lock);
-	
-	STAILQ_INSERT_TAIL(&softc->be_list, be, links);
-
-	softc->num_backends++;
-
-	/*
-	 * Don't want to increment the usage count for internal consumers,
-	 * we won't be able to unload otherwise.
-	 */
-	/* XXX KDM find a substitute for this? */
-#if 0
-	if ((be->flags & CTL_BE_FLAG_INTERNAL) == 0)
-		MOD_INC_USE_COUNT;
-#endif
-
 #ifdef CS_BE_CONFIG_MOVE_DONE_IS_NOT_USED
 	be->config_move_done = ctl_config_move_done;
 #endif
-	/* XXX KDM fix this! */
 	be->num_luns = 0;
-#if 0
-	atomic_set(&be->num_luns, 0);
-#endif
 
-	mtx_unlock(&softc->ctl_lock);
+	/* Call the backend's initialization routine. */
+	if (be->init != NULL) {
+		if ((error = be->init()) != 0) {
+			printf("%s backend init error: %d\n",
+			    be->name, error);
+			return (error);
+		}
+	}
 
+	mtx_lock(&softc->ctl_lock);
+	STAILQ_INSERT_TAIL(&softc->be_list, be, links);
+	softc->num_backends++;
+	mtx_unlock(&softc->ctl_lock);
 	return (0);
 }
 
@@ -119,30 +103,21 @@ int
 ctl_backend_deregister(struct ctl_backend_driver *be)
 {
 	struct ctl_softc *softc = control_softc;
-
-	mtx_lock(&softc->ctl_lock);
-
-#if 0
-	if (atomic_read(&be->num_luns) != 0) {
-#endif
-	/* XXX KDM fix this! */
-	if (be->num_luns != 0) {
-		mtx_unlock(&softc->ctl_lock);
-		return (-1);
+	int error;
+
+	/* Call the backend's shutdown routine. */
+	if (be->shutdown != NULL) {
+		if ((error = be->shutdown()) != 0) {
+			printf("%s backend shutdown error: %d\n",
+			    be->name, error);
+			return (error);
+		}
 	}
 
+	mtx_lock(&softc->ctl_lock);
 	STAILQ_REMOVE(&softc->be_list, be, ctl_backend_driver, links);
-
 	softc->num_backends--;
-
-	/* XXX KDM find a substitute for this? */
-#if 0
-	if ((be->flags & CTL_BE_FLAG_INTERNAL) == 0)
-		MOD_DEC_USE_COUNT;
-#endif
-
 	mtx_unlock(&softc->ctl_lock);
-
 	return (0);
 }
 
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