Commit 9f85a4bb authored by Rusty Russell's avatar Rusty Russell
Browse files

module: refactor load_module part 4 



Allocate references inside module_unload_init(), clean up inside
module_unload_free().

This version fixed to do allocation before __this_cpu_write, thanks to
bug reports from linux-next from Dave Young <hidave.darkstar@gmail.com>
and Stephen Rothwell <sfr@canb.auug.org.au>.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 40dd2560

kernel/module.c

+15 −17
Original line number Diff line number Diff line
@@ -524,8 +524,12 @@ static char last_unloaded_module[MODULE_NAME_LEN+1]; 
EXPORT_TRACEPOINT_SYMBOL(module_get);



/* Init the unload section of the module. */

static void module_unload_init(struct module *mod)

static int module_unload_init(struct module *mod)

{

	mod->refptr = alloc_percpu(struct module_ref);

	if (!mod->refptr)

		return -ENOMEM;



	INIT_LIST_HEAD(&mod->source_list);

	INIT_LIST_HEAD(&mod->target_list);
@@ -533,6 +537,8 @@ static void module_unload_init(struct module *mod) 
	__this_cpu_write(mod->refptr->incs, 1);

	/* Backwards compatibility macros put refcount during init. */

	mod->waiter = current;



	return 0;

}



/* Does a already use b? */
@@ -612,6 +618,8 @@ static void module_unload_free(struct module *mod) 
		kfree(use);

	}

	mutex_unlock(&module_mutex);



	free_percpu(mod->refptr);

}



#ifdef CONFIG_MODULE_FORCE_UNLOAD
@@ -885,8 +893,9 @@ int ref_module(struct module *a, struct module *b) 
}

EXPORT_SYMBOL_GPL(ref_module);



static inline void module_unload_init(struct module *mod)

static inline int module_unload_init(struct module *mod)

{

	return 0;

}

#endif /* CONFIG_MODULE_UNLOAD */
@@ -1559,10 +1568,7 @@ static void free_module(struct module *mod) 
	module_free(mod, mod->module_init);

	kfree(mod->args);

	percpu_modfree(mod);

#if defined(CONFIG_MODULE_UNLOAD)

	if (mod->refptr)

		free_percpu(mod->refptr);

#endif



	/* Free lock-classes: */

	lockdep_free_key_range(mod->module_core, mod->core_size);
@@ -2442,15 +2448,10 @@ static noinline struct module *load_module(void __user *umod, 
		goto free_percpu;

	}



#if defined(CONFIG_MODULE_UNLOAD)

	mod->refptr = alloc_percpu(struct module_ref);

	if (!mod->refptr) {

		err = -ENOMEM;

		goto free_init;

	}

#endif

	/* Now we've moved module, initialize linked lists, etc. */

	module_unload_init(mod);

	err = module_unload_init(mod);

	if (err)

		goto free_init;



	/* Set up license info based on the info section */

	set_license(mod, get_modinfo(sechdrs, infoindex, "license"));
@@ -2619,10 +2620,7 @@ static noinline struct module *load_module(void __user *umod, 
 cleanup:

	free_modinfo(mod);

	module_unload_free(mod);

#if defined(CONFIG_MODULE_UNLOAD)

	free_percpu(mod->refptr);

 free_init:

#endif

	module_free(mod, mod->module_init);

	module_free(mod, mod->module_core);

	/* mod will be freed with core. Don't access it beyond this line! */

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