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authorLinus Torvalds <torvalds@linux-foundation.org>2015-07-01 10:49:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-07-01 10:49:25 -0700
commit02201e3f1b46aed7c6348f406b7b40de80ba6de3 (patch)
tree2392c9098359725c195dd82a72b20ccedc1a1509 /kernel
parent0890a264794f33df540fbaf274699146903b4e6b (diff)
parent20bdc2cfdbc484777b30b96fcdbb8994038f3ce1 (diff)
downloadlinux-sh-02201e3f1b46aed7c6348f406b7b40de80ba6de3.tar.gz
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() ...
Diffstat (limited to 'kernel')
-rw-r--r--kernel/jump_label.c10
-rw-r--r--kernel/module.c309
-rw-r--r--kernel/params.c116
-rw-r--r--kernel/time/timekeeping.c29
-rw-r--r--kernel/workqueue.c7
5 files changed, 328 insertions, 143 deletions
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index 9019f15deab2..52ebaca1b9fc 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 f80a97f7da1f..3e0e19763d24 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 30288c1e15dd..b6554aa71094 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 30b7a409bf1e..bca3667a2de1 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 5243d4b03087..4c4f06176f74 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 */