Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus

* git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus:
  module: convert to stop_machine_create/destroy.
  stop_machine: introduce stop_machine_create/destroy.
  parisc: fix module loading failure of large kernel modules
  module: fix module loading failure of large kernel modules for parisc
  module: fix warning of unused function when !CONFIG_PROC_FS
  kernel/module.c: compare symbol values when marking symbols as exported in /proc/kallsyms.
  remove CONFIG_KMOD

3 files changed, 94 insertions, 26 deletions

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 47fff3b..30e74dd 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -269,8 +269,11 @@ out_release:
 
 int __ref cpu_down(unsigned int cpu)
 {
-	int err = 0;
+	int err;
 
+	err = stop_machine_create();
+	if (err)
+		return err;
 	cpu_maps_update_begin();
 
 	if (cpu_hotplug_disabled) {
@@ -297,6 +300,7 @@ int __ref cpu_down(unsigned int cpu)
 
 out:
 	cpu_maps_update_done();
+	stop_machine_destroy();
 	return err;
 }
 EXPORT_SYMBOL(cpu_down);
diff --git a/kernel/module.c b/kernel/module.c
index dd2a541..f47cce9 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -757,8 +757,16 @@ sys_delete_module(const char __user *name_user, unsigned int flags)
 		return -EFAULT;
 	name[MODULE_NAME_LEN-1] = '\0';
 
-	if (mutex_lock_interruptible(&module_mutex) != 0)
-		return -EINTR;
+	/* Create stop_machine threads since free_module relies on
+	 * a non-failing stop_machine call. */
+	ret = stop_machine_create();
+	if (ret)
+		return ret;
+
+	if (mutex_lock_interruptible(&module_mutex) != 0) {
+		ret = -EINTR;
+		goto out_stop;
+	}
 
 	mod = find_module(name);
 	if (!mod) {
@@ -817,10 +825,12 @@ sys_delete_module(const char __user *name_user, unsigned int flags)
 
  out:
 	mutex_unlock(&module_mutex);
+out_stop:
+	stop_machine_destroy();
 	return ret;
 }
 
-static void print_unload_info(struct seq_file *m, struct module *mod)
+static inline void print_unload_info(struct seq_file *m, struct module *mod)
 {
 	struct module_use *use;
 	int printed_something = 0;
@@ -893,7 +903,7 @@ void module_put(struct module *module)
 EXPORT_SYMBOL(module_put);
 
 #else /* !CONFIG_MODULE_UNLOAD */
-static void print_unload_info(struct seq_file *m, struct module *mod)
+static inline void print_unload_info(struct seq_file *m, struct module *mod)
 {
 	/* We don't know the usage count, or what modules are using. */
 	seq_printf(m, " - -");
@@ -1578,11 +1588,21 @@ static int simplify_symbols(Elf_Shdr *sechdrs,
 	return ret;
 }
 
+/* Additional bytes needed by arch in front of individual sections */
+unsigned int __weak arch_mod_section_prepend(struct module *mod,
+					     unsigned int section)
+{
+	/* default implementation just returns zero */
+	return 0;
+}
+
 /* Update size with this section: return offset. */
-static long get_offset(unsigned int *size, Elf_Shdr *sechdr)
+static long get_offset(struct module *mod, unsigned int *size,
+		       Elf_Shdr *sechdr, unsigned int section)
 {
 	long ret;
 
+	*size += arch_mod_section_prepend(mod, section);
 	ret = ALIGN(*size, sechdr->sh_addralign ?: 1);
 	*size = ret + sechdr->sh_size;
 	return ret;
@@ -1622,7 +1642,7 @@ static void layout_sections(struct module *mod,
 			    || strncmp(secstrings + s->sh_name,
 				       ".init", 5) == 0)
 				continue;
-			s->sh_entsize = get_offset(&mod->core_size, s);
+			s->sh_entsize = get_offset(mod, &mod->core_size, s, i);
 			DEBUGP("\t%s\n", secstrings + s->sh_name);
 		}
 		if (m == 0)
@@ -1640,7 +1660,7 @@ static void layout_sections(struct module *mod,
 			    || strncmp(secstrings + s->sh_name,
 				       ".init", 5) != 0)
 				continue;
-			s->sh_entsize = (get_offset(&mod->init_size, s)
+			s->sh_entsize = (get_offset(mod, &mod->init_size, s, i)
 					 | INIT_OFFSET_MASK);
 			DEBUGP("\t%s\n", secstrings + s->sh_name);
 		}
@@ -1725,15 +1745,15 @@ static const struct kernel_symbol *lookup_symbol(const char *name,
 	return NULL;
 }
 
-static int is_exported(const char *name, const struct module *mod)
+static int is_exported(const char *name, unsigned long value,
+		       const struct module *mod)
 {
-	if (!mod && lookup_symbol(name, __start___ksymtab, __stop___ksymtab))
-		return 1;
+	const struct kernel_symbol *ks;
+	if (!mod)
+		ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
 	else
-		if (mod && lookup_symbol(name, mod->syms, mod->syms + mod->num_syms))
-			return 1;
-		else
-			return 0;
+		ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
+	return ks != NULL && ks->value == value;
 }
 
 /* As per nm */
@@ -1865,6 +1885,13 @@ static noinline struct module *load_module(void __user *umod,
 	/* vmalloc barfs on "unusual" numbers.  Check here */
 	if (len > 64 * 1024 * 1024 || (hdr = vmalloc(len)) == NULL)
 		return ERR_PTR(-ENOMEM);
+
+	/* Create stop_machine threads since the error path relies on
+	 * a non-failing stop_machine call. */
+	err = stop_machine_create();
+	if (err)
+		goto free_hdr;
+
 	if (copy_from_user(hdr, umod, len) != 0) {
 		err = -EFAULT;
 		goto free_hdr;
@@ -2248,6 +2275,7 @@ static noinline struct module *load_module(void __user *umod,
 	/* Get rid of temporary copy */
 	vfree(hdr);
 
+	stop_machine_destroy();
 	/* Done! */
 	return mod;
 
@@ -2270,6 +2298,7 @@ static noinline struct module *load_module(void __user *umod,
 	kfree(args);
  free_hdr:
 	vfree(hdr);
+	stop_machine_destroy();
 	return ERR_PTR(err);
 
  truncated:
@@ -2504,7 +2533,7 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 			strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
 				KSYM_NAME_LEN);
 			strlcpy(module_name, mod->name, MODULE_NAME_LEN);
-			*exported = is_exported(name, mod);
+			*exported = is_exported(name, *value, mod);
 			preempt_enable();
 			return 0;
 		}
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 286c417..0cd415e 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -38,7 +38,10 @@ struct stop_machine_data {
 static unsigned int num_threads;
 static atomic_t thread_ack;
 static DEFINE_MUTEX(lock);
-
+/* setup_lock protects refcount, stop_machine_wq and stop_machine_work. */
+static DEFINE_MUTEX(setup_lock);
+/* Users of stop_machine. */
+static int refcount;
 static struct workqueue_struct *stop_machine_wq;
 static struct stop_machine_data active, idle;
 static const cpumask_t *active_cpus;
@@ -109,6 +112,43 @@ static int chill(void *unused)
 	return 0;
 }
 
+int stop_machine_create(void)
+{
+	mutex_lock(&setup_lock);
+	if (refcount)
+		goto done;
+	stop_machine_wq = create_rt_workqueue("kstop");
+	if (!stop_machine_wq)
+		goto err_out;
+	stop_machine_work = alloc_percpu(struct work_struct);
+	if (!stop_machine_work)
+		goto err_out;
+done:
+	refcount++;
+	mutex_unlock(&setup_lock);
+	return 0;
+
+err_out:
+	if (stop_machine_wq)
+		destroy_workqueue(stop_machine_wq);
+	mutex_unlock(&setup_lock);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL_GPL(stop_machine_create);
+
+void stop_machine_destroy(void)
+{
+	mutex_lock(&setup_lock);
+	refcount--;
+	if (refcount)
+		goto done;
+	destroy_workqueue(stop_machine_wq);
+	free_percpu(stop_machine_work);
+done:
+	mutex_unlock(&setup_lock);
+}
+EXPORT_SYMBOL_GPL(stop_machine_destroy);
+
 int __stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus)
 {
 	struct work_struct *sm_work;
@@ -146,19 +186,14 @@ int stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus)
 {
 	int ret;
 
+	ret = stop_machine_create();
+	if (ret)
+		return ret;
 	/* No CPUs can come up or down during this. */
 	get_online_cpus();
 	ret = __stop_machine(fn, data, cpus);
 	put_online_cpus();
-
+	stop_machine_destroy();
 	return ret;
 }
 EXPORT_SYMBOL_GPL(stop_machine);
-
-static int __init stop_machine_init(void)
-{
-	stop_machine_wq = create_rt_workqueue("kstop");
-	stop_machine_work = alloc_percpu(struct work_struct);
-	return 0;
-}
-core_initcall(stop_machine_init);