Now that module references properly handle the usage of file handlers
and FLBs during active sessions, we can safely remove the
luo_session_quiesce() and luo_session_resume() mechanism.

Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
 kernel/liveupdate/luo_file.c     | 31 +++-------------------
 kernel/liveupdate/luo_flb.c      | 31 +++++-----------------
 kernel/liveupdate/luo_internal.h |  2 --
 kernel/liveupdate/luo_session.c  | 44 --------------------------------
 4 files changed, 9 insertions(+), 99 deletions(-)

diff --git a/kernel/liveupdate/luo_file.c b/kernel/liveupdate/luo_file.c
index 0fe2f8be8bd1..bfa0b4868746 100644
--- a/kernel/liveupdate/luo_file.c
+++ b/kernel/liveupdate/luo_file.c
@@ -847,7 +847,6 @@ void luo_file_set_destroy(struct luo_file_set *file_set)
 int liveupdate_register_file_handler(struct liveupdate_file_handler *fh)
 {
 	struct liveupdate_file_handler *fh_iter;
-	int err;
 
 	if (!liveupdate_enabled())
 		return -EOPNOTSUPP;
@@ -858,45 +857,29 @@ int liveupdate_register_file_handler(struct liveupdate_file_handler *fh)
 		return -EINVAL;
 	}
 
-	/*
-	 * Ensure the system is quiescent (no active sessions).
-	 * This prevents registering new handlers while sessions are active or
-	 * while deserialization is in progress.
-	 */
-	if (!luo_session_quiesce())
-		return -EBUSY;
-
 	scoped_guard(rwsem_write, &luo_file_handler_lock) {
 		/* Check for duplicate compatible strings */
 		list_private_for_each_entry(fh_iter, &luo_file_handler_list, list) {
 			if (!strcmp(fh_iter->compatible, fh->compatible)) {
 				pr_err("File handler registration failed: Compatible string '%s' already registered.\n",
 				       fh->compatible);
-				err = -EEXIST;
-				goto err_resume;
+				return -EEXIST;
 			}
 		}
 
 		/* Pin the module implementing the handler */
-		if (!try_module_get(fh->ops->owner)) {
-			err = -EAGAIN;
-			goto err_resume;
-		}
+		if (!try_module_get(fh->ops->owner))
+			return -EAGAIN;
 
 		INIT_LIST_HEAD(&ACCESS_PRIVATE(fh, flb_list));
 		init_rwsem(&ACCESS_PRIVATE(fh, flb_lock));
 		INIT_LIST_HEAD(&ACCESS_PRIVATE(fh, list));
 		list_add_tail(&ACCESS_PRIVATE(fh, list), &luo_file_handler_list);
 	}
-	luo_session_resume();
 
 	liveupdate_test_register(fh);
 
 	return 0;
-
-err_resume:
-	luo_session_resume();
-	return err;
 }
 
 /**
@@ -921,23 +904,15 @@ void liveupdate_unregister_file_handler(struct liveupdate_file_handler *fh)
 
 	liveupdate_test_unregister(fh);
 
-	if (!luo_session_quiesce())
-		goto err_register;
-
 	scoped_guard(rwsem_write, &luo_file_handler_lock) {
 		is_empty = list_empty(&ACCESS_PRIVATE(fh, flb_list));
 		if (is_empty)
 			list_del(&ACCESS_PRIVATE(fh, list));
 	}
-	luo_session_resume();
 
 	if (!is_empty) {
 		pr_warn("Failed to unregister file handler '%s': FLB list not empty\n",
 			fh->compatible);
 		liveupdate_test_register(fh);
 	}
-	return;
-
-err_register:
-	liveupdate_test_register(fh);
 }
diff --git a/kernel/liveupdate/luo_flb.c b/kernel/liveupdate/luo_flb.c
index 23fa6e0c6083..8810595c672d 100644
--- a/kernel/liveupdate/luo_flb.c
+++ b/kernel/liveupdate/luo_flb.c
@@ -346,7 +346,6 @@ int liveupdate_register_flb(struct liveupdate_file_handler *fh,
 	struct luo_flb_link *link __free(kfree) = NULL;
 	struct liveupdate_flb *gflb;
 	struct luo_flb_link *iter;
-	int err;
 
 	if (!liveupdate_enabled())
 		return -EOPNOTSUPP;
@@ -367,22 +366,13 @@ int liveupdate_register_flb(struct liveupdate_file_handler *fh,
 	if (!link)
 		return -ENOMEM;
 
-	/*
-	 * Ensure the system is quiescent (no active sessions).
-	 * This acts as a global lock for registration: no other thread can
-	 * be in this section, and no sessions can be creating/using FDs.
-	 */
-	if (!luo_session_quiesce())
-		return -EBUSY;
-
 	guard(rwsem_write)(&luo_flb_lock);
 	guard(rwsem_write)(&ACCESS_PRIVATE(fh, flb_lock));
 
 	/* Check that this FLB is not already linked to this file handler */
-	err = -EEXIST;
 	list_for_each_entry(iter, flb_list, list) {
 		if (iter->flb == flb)
-			goto err_resume;
+			return -EEXIST;
 	}
 
 	/*
@@ -390,20 +380,16 @@ int liveupdate_register_flb(struct liveupdate_file_handler *fh,
 	 * is registered
 	 */
 	if (!private->users) {
-		if (WARN_ON(!list_empty(&private->list))) {
-			err = -EINVAL;
-			goto err_resume;
-		}
+		if (WARN_ON(!list_empty(&private->list)))
+			return -EINVAL;
 
-		if (luo_flb_global.count == LUO_FLB_MAX) {
-			err = -ENOSPC;
-			goto err_resume;
-		}
+		if (luo_flb_global.count == LUO_FLB_MAX)
+			return -ENOSPC;
 
 		/* Check that compatible string is unique in global list */
 		list_private_for_each_entry(gflb, &luo_flb_global.list, private.list) {
 			if (!strcmp(gflb->compatible, flb->compatible))
-				goto err_resume;
+				return -EEXIST;
 		}
 
 		list_add_tail(&private->list, &luo_flb_global.list);
@@ -414,13 +400,8 @@ int liveupdate_register_flb(struct liveupdate_file_handler *fh,
 	private->users++;
 	link->flb = flb;
 	list_add_tail(&no_free_ptr(link)->list, flb_list);
-	luo_session_resume();
 
 	return 0;
-
-err_resume:
-	luo_session_resume();
-	return err;
 }
 
 /**
diff --git a/kernel/liveupdate/luo_internal.h b/kernel/liveupdate/luo_internal.h
index 8083d8739b09..ec949f91c8c1 100644
--- a/kernel/liveupdate/luo_internal.h
+++ b/kernel/liveupdate/luo_internal.h
@@ -83,8 +83,6 @@ int __init luo_session_setup_outgoing(void *fdt);
 int __init luo_session_setup_incoming(void *fdt);
 int luo_session_serialize(void);
 int luo_session_deserialize(void);
-bool luo_session_quiesce(void);
-void luo_session_resume(void);
 
 int luo_preserve_file(struct luo_file_set *file_set, u64 token, int fd);
 void luo_file_unpreserve_files(struct luo_file_set *file_set);
diff --git a/kernel/liveupdate/luo_session.c b/kernel/liveupdate/luo_session.c
index 783677295640..067ffb54c36a 100644
--- a/kernel/liveupdate/luo_session.c
+++ b/kernel/liveupdate/luo_session.c
@@ -600,47 +600,3 @@ int luo_session_serialize(void)
 
 	return err;
 }
-
-/**
- * luo_session_quiesce - Ensure no active sessions exist and lock session lists.
- *
- * Acquires exclusive write locks on both incoming and outgoing session lists.
- * It then validates no sessions exist in either list.
- *
- * This mechanism is used during file handler un/registration to ensure that no
- * sessions are currently using the handler, and no new sessions can be created
- * while un/registration is in progress.
- *
- * This prevents registering new handlers while sessions are active or
- * while deserialization is in progress.
- *
- * Return:
- * true  - System is quiescent (0 sessions) and locked.
- * false - Active sessions exist. The locks are released internally.
- */
-bool luo_session_quiesce(void)
-{
-	down_write(&luo_session_global.incoming.rwsem);
-	down_write(&luo_session_global.outgoing.rwsem);
-
-	if (luo_session_global.incoming.count ||
-	    luo_session_global.outgoing.count) {
-		up_write(&luo_session_global.outgoing.rwsem);
-		up_write(&luo_session_global.incoming.rwsem);
-		return false;
-	}
-
-	return true;
-}
-
-/**
- * luo_session_resume - Unlock session lists and resume normal activity.
- *
- * Releases the exclusive locks acquired by a successful call to
- * luo_session_quiesce().
- */
-void luo_session_resume(void)
-{
-	up_write(&luo_session_global.outgoing.rwsem);
-	up_write(&luo_session_global.incoming.rwsem);
-}
-- 
2.53.0.851.ga537e3e6e9-goog