Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "Main excitement here is Peter Zijlstra's lockless rbtree optimization
  to speed module address lookup.  He found some abusers of the module
  lock doing that too.

  A little bit of parameter work here too; including Dan Streetman's
  breaking up the big param mutex so writing a parameter can load
  another module (yeah, really).  Unfortunately that broke the usual
  suspects, !CONFIG_MODULES and !CONFIG_SYSFS, so those fixes were
  appended too"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (26 commits)
  modules: only use mod->param_lock if CONFIG_MODULES
  param: fix module param locks when !CONFIG_SYSFS.
  rcu: merge fix for Convert ACCESS_ONCE() to READ_ONCE() and WRITE_ONCE()
  module: add per-module param_lock
  module: make perm const
  params: suppress unused variable error, warn once just in case code changes.
  modules: clarify CONFIG_MODULE_COMPRESS help, suggest 'N'.
  kernel/module.c: avoid ifdefs for sig_enforce declaration
  kernel/workqueue.c: remove ifdefs over wq_power_efficient
  kernel/params.c: export param_ops_bool_enable_only
  kernel/params.c: generalize bool_enable_only
  kernel/module.c: use generic module param operaters for sig_enforce
  kernel/params: constify struct kernel_param_ops uses
  sysfs: tightened sysfs permission checks
  module: Rework module_addr_{min,max}
  module: Use __module_address() for module_address_lookup()
  module: Make the mod_tree stuff conditional on PERF_EVENTS || TRACING
  module: Optimize __module_address() using a latched RB-tree
  rbtree: Implement generic latch_tree
  seqlock: Introduce raw_read_seqcount_latch()
  ...

5 files changed, 328 insertions, 143 deletions

diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 9019f15..52ebaca 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -302,7 +302,7 @@ static int jump_label_add_module(struct module *mod)
 			continue;
 
 		key = iterk;
-		if (__module_address(iter->key) == mod) {
+		if (within_module(iter->key, mod)) {
 			/*
 			 * Set key->entries to iter, but preserve JUMP_LABEL_TRUE_BRANCH.
 			 */
@@ -339,7 +339,7 @@ static void jump_label_del_module(struct module *mod)
 
 		key = (struct static_key *)(unsigned long)iter->key;
 
-		if (__module_address(iter->key) == mod)
+		if (within_module(iter->key, mod))
 			continue;
 
 		prev = &key->next;
@@ -443,14 +443,16 @@ static void jump_label_update(struct static_key *key, int enable)
 {
 	struct jump_entry *stop = __stop___jump_table;
 	struct jump_entry *entry = jump_label_get_entries(key);
-
 #ifdef CONFIG_MODULES
-	struct module *mod = __module_address((unsigned long)key);
+	struct module *mod;
 
 	__jump_label_mod_update(key, enable);
 
+	preempt_disable();
+	mod = __module_address((unsigned long)key);
 	if (mod)
 		stop = mod->jump_entries + mod->num_jump_entries;
+	preempt_enable();
 #endif
 	/* if there are no users, entry can be NULL */
 	if (entry)
diff --git a/kernel/module.c b/kernel/module.c
index f80a97f..3e0e197 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -101,48 +101,201 @@
 DEFINE_MUTEX(module_mutex);
 EXPORT_SYMBOL_GPL(module_mutex);
 static LIST_HEAD(modules);
-#ifdef CONFIG_KGDB_KDB
-struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
-#endif /* CONFIG_KGDB_KDB */
 
-#ifdef CONFIG_MODULE_SIG
-#ifdef CONFIG_MODULE_SIG_FORCE
-static bool sig_enforce = true;
-#else
-static bool sig_enforce = false;
+#ifdef CONFIG_MODULES_TREE_LOOKUP
+
+/*
+ * Use a latched RB-tree for __module_address(); this allows us to use
+ * RCU-sched lookups of the address from any context.
+ *
+ * Because modules have two address ranges: init and core, we need two
+ * latch_tree_nodes entries. Therefore we need the back-pointer from
+ * mod_tree_node.
+ *
+ * Because init ranges are short lived we mark them unlikely and have placed
+ * them outside the critical cacheline in struct module.
+ *
+ * This is conditional on PERF_EVENTS || TRACING because those can really hit
+ * __module_address() hard by doing a lot of stack unwinding; potentially from
+ * NMI context.
+ */
 
-static int param_set_bool_enable_only(const char *val,
-				      const struct kernel_param *kp)
+static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n)
 {
-	int err;
-	bool test;
-	struct kernel_param dummy_kp = *kp;
+	struct mod_tree_node *mtn = container_of(n, struct mod_tree_node, node);
+	struct module *mod = mtn->mod;
 
-	dummy_kp.arg = &test;
+	if (unlikely(mtn == &mod->mtn_init))
+		return (unsigned long)mod->module_init;
 
-	err = param_set_bool(val, &dummy_kp);
-	if (err)
-		return err;
+	return (unsigned long)mod->module_core;
+}
+
+static __always_inline unsigned long __mod_tree_size(struct latch_tree_node *n)
+{
+	struct mod_tree_node *mtn = container_of(n, struct mod_tree_node, node);
+	struct module *mod = mtn->mod;
 
-	/* Don't let them unset it once it's set! */
-	if (!test && sig_enforce)
-		return -EROFS;
+	if (unlikely(mtn == &mod->mtn_init))
+		return (unsigned long)mod->init_size;
+
+	return (unsigned long)mod->core_size;
+}
+
+static __always_inline bool
+mod_tree_less(struct latch_tree_node *a, struct latch_tree_node *b)
+{
+	return __mod_tree_val(a) < __mod_tree_val(b);
+}
+
+static __always_inline int
+mod_tree_comp(void *key, struct latch_tree_node *n)
+{
+	unsigned long val = (unsigned long)key;
+	unsigned long start, end;
+
+	start = __mod_tree_val(n);
+	if (val < start)
+		return -1;
+
+	end = start + __mod_tree_size(n);
+	if (val >= end)
+		return 1;
 
-	if (test)
-		sig_enforce = true;
 	return 0;
 }
 
-static const struct kernel_param_ops param_ops_bool_enable_only = {
-	.flags = KERNEL_PARAM_OPS_FL_NOARG,
-	.set = param_set_bool_enable_only,
-	.get = param_get_bool,
+static const struct latch_tree_ops mod_tree_ops = {
+	.less = mod_tree_less,
+	.comp = mod_tree_comp,
 };
-#define param_check_bool_enable_only param_check_bool
 
+static struct mod_tree_root {
+	struct latch_tree_root root;
+	unsigned long addr_min;
+	unsigned long addr_max;
+} mod_tree __cacheline_aligned = {
+	.addr_min = -1UL,
+};
+
+#define module_addr_min mod_tree.addr_min
+#define module_addr_max mod_tree.addr_max
+
+static noinline void __mod_tree_insert(struct mod_tree_node *node)
+{
+	latch_tree_insert(&node->node, &mod_tree.root, &mod_tree_ops);
+}
+
+static void __mod_tree_remove(struct mod_tree_node *node)
+{
+	latch_tree_erase(&node->node, &mod_tree.root, &mod_tree_ops);
+}
+
+/*
+ * These modifications: insert, remove_init and remove; are serialized by the
+ * module_mutex.
+ */
+static void mod_tree_insert(struct module *mod)
+{
+	mod->mtn_core.mod = mod;
+	mod->mtn_init.mod = mod;
+
+	__mod_tree_insert(&mod->mtn_core);
+	if (mod->init_size)
+		__mod_tree_insert(&mod->mtn_init);
+}
+
+static void mod_tree_remove_init(struct module *mod)
+{
+	if (mod->init_size)
+		__mod_tree_remove(&mod->mtn_init);
+}
+
+static void mod_tree_remove(struct module *mod)
+{
+	__mod_tree_remove(&mod->mtn_core);
+	mod_tree_remove_init(mod);
+}
+
+static struct module *mod_find(unsigned long addr)
+{
+	struct latch_tree_node *ltn;
+
+	ltn = latch_tree_find((void *)addr, &mod_tree.root, &mod_tree_ops);
+	if (!ltn)
+		return NULL;
+
+	return container_of(ltn, struct mod_tree_node, node)->mod;
+}
+
+#else /* MODULES_TREE_LOOKUP */
+
+static unsigned long module_addr_min = -1UL, module_addr_max = 0;
+
+static void mod_tree_insert(struct module *mod) { }
+static void mod_tree_remove_init(struct module *mod) { }
+static void mod_tree_remove(struct module *mod) { }
+
+static struct module *mod_find(unsigned long addr)
+{
+	struct module *mod;
+
+	list_for_each_entry_rcu(mod, &modules, list) {
+		if (within_module(addr, mod))
+			return mod;
+	}
+
+	return NULL;
+}
+
+#endif /* MODULES_TREE_LOOKUP */
+
+/*
+ * Bounds of module text, for speeding up __module_address.
+ * Protected by module_mutex.
+ */
+static void __mod_update_bounds(void *base, unsigned int size)
+{
+	unsigned long min = (unsigned long)base;
+	unsigned long max = min + size;
+
+	if (min < module_addr_min)
+		module_addr_min = min;
+	if (max > module_addr_max)
+		module_addr_max = max;
+}
+
+static void mod_update_bounds(struct module *mod)
+{
+	__mod_update_bounds(mod->module_core, mod->core_size);
+	if (mod->init_size)
+		__mod_update_bounds(mod->module_init, mod->init_size);
+}
+
+#ifdef CONFIG_KGDB_KDB
+struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
+#endif /* CONFIG_KGDB_KDB */
+
+static void module_assert_mutex(void)
+{
+	lockdep_assert_held(&module_mutex);
+}
+
+static void module_assert_mutex_or_preempt(void)
+{
+#ifdef CONFIG_LOCKDEP
+	if (unlikely(!debug_locks))
+		return;
+
+	WARN_ON(!rcu_read_lock_sched_held() &&
+		!lockdep_is_held(&module_mutex));
+#endif
+}
+
+static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
+#ifndef CONFIG_MODULE_SIG_FORCE
 module_param(sig_enforce, bool_enable_only, 0644);
 #endif /* !CONFIG_MODULE_SIG_FORCE */
-#endif /* CONFIG_MODULE_SIG */
 
 /* Block module loading/unloading? */
 int modules_disabled = 0;
@@ -153,10 +306,6 @@ static DECLARE_WAIT_QUEUE_HEAD(module_wq);
 
 static BLOCKING_NOTIFIER_HEAD(module_notify_list);
 
-/* Bounds of module allocation, for speeding __module_address.
- * Protected by module_mutex. */
-static unsigned long module_addr_min = -1UL, module_addr_max = 0;
-
 int register_module_notifier(struct notifier_block *nb)
 {
 	return blocking_notifier_chain_register(&module_notify_list, nb);
@@ -318,6 +467,8 @@ bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
 #endif
 	};
 
+	module_assert_mutex_or_preempt();
+
 	if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
 		return true;
 
@@ -457,6 +608,8 @@ static struct module *find_module_all(const char *name, size_t len,
 {
 	struct module *mod;
 
+	module_assert_mutex();
+
 	list_for_each_entry(mod, &modules, list) {
 		if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
 			continue;
@@ -1169,11 +1322,17 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
 {
 	const unsigned long *crc;
 
-	/* Since this should be found in kernel (which can't be removed),
-	 * no locking is necessary. */
+	/*
+	 * Since this should be found in kernel (which can't be removed), no
+	 * locking is necessary -- use preempt_disable() to placate lockdep.
+	 */
+	preempt_disable();
 	if (!find_symbol(VMLINUX_SYMBOL_STR(module_layout), NULL,
-			 &crc, true, false))
+			 &crc, true, false)) {
+		preempt_enable();
 		BUG();
+	}
+	preempt_enable();
 	return check_version(sechdrs, versindex,
 			     VMLINUX_SYMBOL_STR(module_layout), mod, crc,
 			     NULL);
@@ -1661,6 +1820,10 @@ static void mod_sysfs_fini(struct module *mod)
 	mod_kobject_put(mod);
 }
 
+static void init_param_lock(struct module *mod)
+{
+	mutex_init(&mod->param_lock);
+}
 #else /* !CONFIG_SYSFS */
 
 static int mod_sysfs_setup(struct module *mod,
@@ -1683,6 +1846,9 @@ static void del_usage_links(struct module *mod)
 {
 }
 
+static void init_param_lock(struct module *mod)
+{
+}
 #endif /* CONFIG_SYSFS */
 
 static void mod_sysfs_teardown(struct module *mod)
@@ -1852,10 +2018,11 @@ static void free_module(struct module *mod)
 	mutex_lock(&module_mutex);
 	/* Unlink carefully: kallsyms could be walking list. */
 	list_del_rcu(&mod->list);
+	mod_tree_remove(mod);
 	/* Remove this module from bug list, this uses list_del_rcu */
 	module_bug_cleanup(mod);
-	/* Wait for RCU synchronizing before releasing mod->list and buglist. */
-	synchronize_rcu();
+	/* Wait for RCU-sched synchronizing before releasing mod->list and buglist. */
+	synchronize_sched();
 	mutex_unlock(&module_mutex);
 
 	/* This may be NULL, but that's OK */
@@ -2384,22 +2551,6 @@ void * __weak module_alloc(unsigned long size)
 	return vmalloc_exec(size);
 }
 
-static void *module_alloc_update_bounds(unsigned long size)
-{
-	void *ret = module_alloc(size);
-
-	if (ret) {
-		mutex_lock(&module_mutex);
-		/* Update module bounds. */
-		if ((unsigned long)ret < module_addr_min)
-			module_addr_min = (unsigned long)ret;
-		if ((unsigned long)ret + size > module_addr_max)
-			module_addr_max = (unsigned long)ret + size;
-		mutex_unlock(&module_mutex);
-	}
-	return ret;
-}
-
 #ifdef CONFIG_DEBUG_KMEMLEAK
 static void kmemleak_load_module(const struct module *mod,
 				 const struct load_info *info)
@@ -2805,7 +2956,7 @@ static int move_module(struct module *mod, struct load_info *info)
 	void *ptr;
 
 	/* Do the allocs. */
-	ptr = module_alloc_update_bounds(mod->core_size);
+	ptr = module_alloc(mod->core_size);
 	/*
 	 * The pointer to this block is stored in the module structure
 	 * which is inside the block. Just mark it as not being a
@@ -2819,7 +2970,7 @@ static int move_module(struct module *mod, struct load_info *info)
 	mod->module_core = ptr;
 
 	if (mod->init_size) {
-		ptr = module_alloc_update_bounds(mod->init_size);
+		ptr = module_alloc(mod->init_size);
 		/*
 		 * The pointer to this block is stored in the module structure
 		 * which is inside the block. This block doesn't need to be
@@ -3119,6 +3270,7 @@ static noinline int do_init_module(struct module *mod)
 	mod->symtab = mod->core_symtab;
 	mod->strtab = mod->core_strtab;
 #endif
+	mod_tree_remove_init(mod);
 	unset_module_init_ro_nx(mod);
 	module_arch_freeing_init(mod);
 	mod->module_init = NULL;
@@ -3127,11 +3279,11 @@ static noinline int do_init_module(struct module *mod)
 	mod->init_text_size = 0;
 	/*
 	 * We want to free module_init, but be aware that kallsyms may be
-	 * walking this with preempt disabled.  In all the failure paths,
-	 * we call synchronize_rcu/synchronize_sched, but we don't want
-	 * to slow down the success path, so use actual RCU here.
+	 * walking this with preempt disabled.  In all the failure paths, we
+	 * call synchronize_sched(), but we don't want to slow down the success
+	 * path, so use actual RCU here.
 	 */
-	call_rcu(&freeinit->rcu, do_free_init);
+	call_rcu_sched(&freeinit->rcu, do_free_init);
 	mutex_unlock(&module_mutex);
 	wake_up_all(&module_wq);
 
@@ -3188,7 +3340,9 @@ again:
 		err = -EEXIST;
 		goto out;
 	}
+	mod_update_bounds(mod);
 	list_add_rcu(&mod->list, &modules);
+	mod_tree_insert(mod);
 	err = 0;
 
 out:
@@ -3304,6 +3458,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	if (err)
 		goto unlink_mod;
 
+	init_param_lock(mod);
+
 	/* Now we've got everything in the final locations, we can
 	 * find optional sections. */
 	err = find_module_sections(mod, info);
@@ -3402,8 +3558,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	/* Unlink carefully: kallsyms could be walking list. */
 	list_del_rcu(&mod->list);
 	wake_up_all(&module_wq);
-	/* Wait for RCU synchronizing before releasing mod->list. */
-	synchronize_rcu();
+	/* Wait for RCU-sched synchronizing before releasing mod->list. */
+	synchronize_sched();
 	mutex_unlock(&module_mutex);
  free_module:
 	/* Free lock-classes; relies on the preceding sync_rcu() */
@@ -3527,19 +3683,15 @@ const char *module_address_lookup(unsigned long addr,
 			    char **modname,
 			    char *namebuf)
 {
-	struct module *mod;
 	const char *ret = NULL;
+	struct module *mod;
 
 	preempt_disable();
-	list_for_each_entry_rcu(mod, &modules, list) {
-		if (mod->state == MODULE_STATE_UNFORMED)
-			continue;
-		if (within_module(addr, mod)) {
-			if (modname)
-				*modname = mod->name;
-			ret = get_ksymbol(mod, addr, size, offset);
-			break;
-		}
+	mod = __module_address(addr);
+	if (mod) {
+		if (modname)
+			*modname = mod->name;
+		ret = get_ksymbol(mod, addr, size, offset);
 	}
 	/* Make a copy in here where it's safe */
 	if (ret) {
@@ -3547,6 +3699,7 @@ const char *module_address_lookup(unsigned long addr,
 		ret = namebuf;
 	}
 	preempt_enable();
+
 	return ret;
 }
 
@@ -3670,6 +3823,8 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 	unsigned int i;
 	int ret;
 
+	module_assert_mutex();
+
 	list_for_each_entry(mod, &modules, list) {
 		if (mod->state == MODULE_STATE_UNFORMED)
 			continue;
@@ -3844,13 +3999,15 @@ struct module *__module_address(unsigned long addr)
 	if (addr < module_addr_min || addr > module_addr_max)
 		return NULL;
 
-	list_for_each_entry_rcu(mod, &modules, list) {
+	module_assert_mutex_or_preempt();
+
+	mod = mod_find(addr);
+	if (mod) {
+		BUG_ON(!within_module(addr, mod));
 		if (mod->state == MODULE_STATE_UNFORMED)
-			continue;
-		if (within_module(addr, mod))
-			return mod;
+			mod = NULL;
 	}
-	return NULL;
+	return mod;
 }
 EXPORT_SYMBOL_GPL(__module_address);
 
diff --git a/kernel/params.c b/kernel/params.c
index 30288c1..b6554aa 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -25,15 +25,34 @@
 #include <linux/slab.h>
 #include <linux/ctype.h>
 
-/* Protects all parameters, and incidentally kmalloced_param list. */
+#ifdef CONFIG_SYSFS
+/* Protects all built-in parameters, modules use their own param_lock */
 static DEFINE_MUTEX(param_lock);
 
+/* Use the module's mutex, or if built-in use the built-in mutex */
+#ifdef CONFIG_MODULES
+#define KPARAM_MUTEX(mod)	((mod) ? &(mod)->param_lock : &param_lock)
+#else
+#define KPARAM_MUTEX(mod)	(&param_lock)
+#endif
+
+static inline void check_kparam_locked(struct module *mod)
+{
+	BUG_ON(!mutex_is_locked(KPARAM_MUTEX(mod)));
+}
+#else
+static inline void check_kparam_locked(struct module *mod)
+{
+}
+#endif /* !CONFIG_SYSFS */
+
 /* This just allows us to keep track of which parameters are kmalloced. */
 struct kmalloced_param {
 	struct list_head list;
 	char val[];
 };
 static LIST_HEAD(kmalloced_params);
+static DEFINE_SPINLOCK(kmalloced_params_lock);
 
 static void *kmalloc_parameter(unsigned int size)
 {
@@ -43,7 +62,10 @@ static void *kmalloc_parameter(unsigned int size)
 	if (!p)
 		return NULL;
 
+	spin_lock(&kmalloced_params_lock);
 	list_add(&p->list, &kmalloced_params);
+	spin_unlock(&kmalloced_params_lock);
+
 	return p->val;
 }
 
@@ -52,6 +74,7 @@ static void maybe_kfree_parameter(void *param)
 {
 	struct kmalloced_param *p;
 
+	spin_lock(&kmalloced_params_lock);
 	list_for_each_entry(p, &kmalloced_params, list) {
 		if (p->val == param) {
 			list_del(&p->list);
@@ -59,6 +82,7 @@ static void maybe_kfree_parameter(void *param)
 			break;
 		}
 	}
+	spin_unlock(&kmalloced_params_lock);
 }
 
 static char dash2underscore(char c)
@@ -119,10 +143,10 @@ static int parse_one(char *param,
 				return -EINVAL;
 			pr_debug("handling %s with %p\n", param,
 				params[i].ops->set);
-			mutex_lock(&param_lock);
+			kernel_param_lock(params[i].mod);
 			param_check_unsafe(&params[i]);
 			err = params[i].ops->set(val, &params[i]);
-			mutex_unlock(&param_lock);
+			kernel_param_unlock(params[i].mod);
 			return err;
 		}
 	}
@@ -254,7 +278,7 @@ char *parse_args(const char *doing,
 		return scnprintf(buffer, PAGE_SIZE, format,		\
 				*((type *)kp->arg));			\
 	}								\
-	struct kernel_param_ops param_ops_##name = {			\
+	const struct kernel_param_ops param_ops_##name = {			\
 		.set = param_set_##name,				\
 		.get = param_get_##name,				\
 	};								\
@@ -306,7 +330,7 @@ static void param_free_charp(void *arg)
 	maybe_kfree_parameter(*((char **)arg));
 }
 
-struct kernel_param_ops param_ops_charp = {
+const struct kernel_param_ops param_ops_charp = {
 	.set = param_set_charp,
 	.get = param_get_charp,
 	.free = param_free_charp,
@@ -331,13 +355,44 @@ int param_get_bool(char *buffer, const struct kernel_param *kp)
 }
 EXPORT_SYMBOL(param_get_bool);
 
-struct kernel_param_ops param_ops_bool = {
+const struct kernel_param_ops param_ops_bool = {
 	.flags = KERNEL_PARAM_OPS_FL_NOARG,
 	.set = param_set_bool,
 	.get = param_get_bool,
 };
 EXPORT_SYMBOL(param_ops_bool);
 
+int param_set_bool_enable_only(const char *val, const struct kernel_param *kp)
+{
+	int err = 0;
+	bool new_value;
+	bool orig_value = *(bool *)kp->arg;
+	struct kernel_param dummy_kp = *kp;
+
+	dummy_kp.arg = &new_value;
+
+	err = param_set_bool(val, &dummy_kp);
+	if (err)
+		return err;
+
+	/* Don't let them unset it once it's set! */
+	if (!new_value && orig_value)
+		return -EROFS;
+
+	if (new_value)
+		err = param_set_bool(val, kp);
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(param_set_bool_enable_only);
+
+const struct kernel_param_ops param_ops_bool_enable_only = {
+	.flags = KERNEL_PARAM_OPS_FL_NOARG,
+	.set = param_set_bool_enable_only,
+	.get = param_get_bool,
+};
+EXPORT_SYMBOL_GPL(param_ops_bool_enable_only);
+
 /* This one must be bool. */
 int param_set_invbool(const char *val, const struct kernel_param *kp)
 {
@@ -359,7 +414,7 @@ int param_get_invbool(char *buffer, const struct kernel_param *kp)
 }
 EXPORT_SYMBOL(param_get_invbool);
 
-struct kernel_param_ops param_ops_invbool = {
+const struct kernel_param_ops param_ops_invbool = {
 	.set = param_set_invbool,
 	.get = param_get_invbool,
 };
@@ -367,12 +422,11 @@ EXPORT_SYMBOL(param_ops_invbool);
 
 int param_set_bint(const char *val, const struct kernel_param *kp)
 {
-	struct kernel_param boolkp;
+	/* Match bool exactly, by re-using it. */
+	struct kernel_param boolkp = *kp;
 	bool v;
 	int ret;
 
-	/* Match bool exactly, by re-using it. */
-	boolkp = *kp;
 	boolkp.arg = &v;
 
 	ret = param_set_bool(val, &boolkp);
@@ -382,7 +436,7 @@ int param_set_bint(const char *val, const struct kernel_param *kp)
 }
 EXPORT_SYMBOL(param_set_bint);
 
-struct kernel_param_ops param_ops_bint = {
+const struct kernel_param_ops param_ops_bint = {
 	.flags = KERNEL_PARAM_OPS_FL_NOARG,
 	.set = param_set_bint,
 	.get = param_get_int,
@@ -390,7 +444,8 @@ struct kernel_param_ops param_ops_bint = {
 EXPORT_SYMBOL(param_ops_bint);
 
 /* We break the rule and mangle the string. */
-static int param_array(const char *name,
+static int param_array(struct module *mod,
+		       const char *name,
 		       const char *val,
 		       unsigned int min, unsigned int max,
 		       void *elem, int elemsize,
@@ -421,7 +476,7 @@ static int param_array(const char *name,
 		/* nul-terminate and parse */
 		save = val[len];
 		((char *)val)[len] = '\0';
-		BUG_ON(!mutex_is_locked(&param_lock));
+		check_kparam_locked(mod);
 		ret = set(val, &kp);
 
 		if (ret != 0)
@@ -443,7 +498,7 @@ static int param_array_set(const char *val, const struct kernel_param *kp)
 	const struct kparam_array *arr = kp->arr;
 	unsigned int temp_num;
 
-	return param_array(kp->name, val, 1, arr->max, arr->elem,
+	return param_array(kp->mod, kp->name, val, 1, arr->max, arr->elem,
 			   arr->elemsize, arr->ops->set, kp->level,
 			   arr->num ?: &temp_num);
 }
@@ -452,14 +507,13 @@ static int param_array_get(char *buffer, const struct kernel_param *kp)
 {
 	int i, off, ret;
 	const struct kparam_array *arr = kp->arr;
-	struct kernel_param p;
+	struct kernel_param p = *kp;
 
-	p = *kp;
 	for (i = off = 0; i < (arr->num ? *arr->num : arr->max); i++) {
 		if (i)
 			buffer[off++] = ',';
 		p.arg = arr->elem + arr->elemsize * i;
-		BUG_ON(!mutex_is_locked(&param_lock));
+		check_kparam_locked(p.mod);
 		ret = arr->ops->get(buffer + off, &p);
 		if (ret < 0)
 			return ret;
@@ -479,7 +533,7 @@ static void param_array_free(void *arg)
 			arr->ops->free(arr->elem + arr->elemsize * i);
 }
 
-struct kernel_param_ops param_array_ops = {
+const struct kernel_param_ops param_array_ops = {
 	.set = param_array_set,
 	.get = param_array_get,
 	.free = param_array_free,
@@ -507,7 +561,7 @@ int param_get_string(char *buffer, const struct kernel_param *kp)
 }
 EXPORT_SYMBOL(param_get_string);
 
-struct kernel_param_ops param_ops_string = {
+const struct kernel_param_ops param_ops_string = {
 	.set = param_set_copystring,
 	.get = param_get_string,
 };
@@ -542,9 +596,9 @@ static ssize_t param_attr_show(struct module_attribute *mattr,
 	if (!attribute->param->ops->get)
 		return -EPERM;
 
-	mutex_lock(&param_lock);
+	kernel_param_lock(mk->mod);
 	count = attribute->param->ops->get(buf, attribute->param);
-	mutex_unlock(&param_lock);
+	kernel_param_unlock(mk->mod);
 	if (count > 0) {
 		strcat(buf, "\n");
 		++count;
@@ -554,7 +608,7 @@ static ssize_t param_attr_show(struct module_attribute *mattr,
 
 /* sysfs always hands a nul-terminated string in buf.  We rely on that. */
 static ssize_t param_attr_store(struct module_attribute *mattr,
-				struct module_kobject *km,
+				struct module_kobject *mk,
 				const char *buf, size_t len)
 {
  	int err;
@@ -563,10 +617,10 @@ static ssize_t param_attr_store(struct module_attribute *mattr,
 	if (!attribute->param->ops->set)
 		return -EPERM;
 
-	mutex_lock(&param_lock);
+	kernel_param_lock(mk->mod);
 	param_check_unsafe(attribute->param);
 	err = attribute->param->ops->set(buf, attribute->param);
-	mutex_unlock(&param_lock);
+	kernel_param_unlock(mk->mod);
 	if (!err)
 		return len;
 	return err;
@@ -580,17 +634,18 @@ static ssize_t param_attr_store(struct module_attribute *mattr,
 #endif
 
 #ifdef CONFIG_SYSFS
-void __kernel_param_lock(void)
+void kernel_param_lock(struct module *mod)
 {
-	mutex_lock(&param_lock);
+	mutex_lock(KPARAM_MUTEX(mod));
 }
-EXPORT_SYMBOL(__kernel_param_lock);
 
-void __kernel_param_unlock(void)
+void kernel_param_unlock(struct module *mod)
 {
-	mutex_unlock(&param_lock);
+	mutex_unlock(KPARAM_MUTEX(mod));
 }
-EXPORT_SYMBOL(__kernel_param_unlock);
+
+EXPORT_SYMBOL(kernel_param_lock);
+EXPORT_SYMBOL(kernel_param_unlock);
 
 /*
  * add_sysfs_param - add a parameter to sysfs
@@ -856,6 +911,7 @@ static void __init version_sysfs_builtin(void)
 		mk = locate_module_kobject(vattr->module_name);
 		if (mk) {
 			err = sysfs_create_file(&mk->kobj, &vattr->mattr.attr);
+			WARN_ON_ONCE(err);
 			kobject_uevent(&mk->kobj, KOBJ_ADD);
 			kobject_put(&mk->kobj);
 		}
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 30b7a40..bca3667 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -319,32 +319,7 @@ static inline s64 timekeeping_get_ns(struct tk_read_base *tkr)
  * We want to use this from any context including NMI and tracing /
  * instrumenting the timekeeping code itself.
  *
- * So we handle this differently than the other timekeeping accessor
- * functions which retry when the sequence count has changed. The
- * update side does:
- *
- * smp_wmb();	<- Ensure that the last base[1] update is visible
- * tkf->seq++;
- * smp_wmb();	<- Ensure that the seqcount update is visible
- * update(tkf->base[0], tkr);
- * smp_wmb();	<- Ensure that the base[0] update is visible
- * tkf->seq++;
- * smp_wmb();	<- Ensure that the seqcount update is visible
- * update(tkf->base[1], tkr);
- *
- * The reader side does:
- *
- * do {
- *	seq = tkf->seq;
- *	smp_rmb();
- *	idx = seq & 0x01;
- *	now = now(tkf->base[idx]);
- *	smp_rmb();
- * } while (seq != tkf->seq)
- *
- * As long as we update base[0] readers are forced off to
- * base[1]. Once base[0] is updated readers are redirected to base[0]
- * and the base[1] update takes place.
+ * Employ the latch technique; see @raw_write_seqcount_latch.
  *
  * So if a NMI hits the update of base[0] then it will use base[1]
  * which is still consistent. In the worst case this can result is a
@@ -407,7 +382,7 @@ static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
 	u64 now;
 
 	do {
-		seq = raw_read_seqcount(&tkf->seq);
+		seq = raw_read_seqcount_latch(&tkf->seq);
 		tkr = tkf->base + (seq & 0x01);
 		now = ktime_to_ns(tkr->base) + timekeeping_get_ns(tkr);
 	} while (read_seqcount_retry(&tkf->seq, seq));
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 5243d4b..4c4f061 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -285,12 +285,7 @@ static bool wq_disable_numa;
 module_param_named(disable_numa, wq_disable_numa, bool, 0444);
 
 /* see the comment above the definition of WQ_POWER_EFFICIENT */
-#ifdef CONFIG_WQ_POWER_EFFICIENT_DEFAULT
-static bool wq_power_efficient = true;
-#else
-static bool wq_power_efficient;
-#endif
-
+static bool wq_power_efficient = IS_ENABLED(CONFIG_WQ_POWER_EFFICIENT_DEFAULT);
 module_param_named(power_efficient, wq_power_efficient, bool, 0444);
 
 static bool wq_numa_enabled;		/* unbound NUMA affinity enabled */