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Commit 3f2b9c9c authored by Rusty Russell's avatar Rusty Russell
Browse files

module: remove rmmod --wait option. 



The option to wait for a module reference count to reach zero was in
the initial module implementation, but it was never supported in
modprobe (you had to use rmmod --wait).  After discussion with Lucas,
It has been deprecated (with a 10 second sleep) in kmod for the last
year.

This finally removes it: the flag will evoke a printk warning and a
normal (non-blocking) remove attempt.

Cc: Lucas De Marchi <lucas.de.marchi@gmail.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent d8524ae9

include/linux/module.h

+0 −3
Original line number Diff line number Diff line
@@ -367,9 +367,6 @@ struct module 
	/* What modules do I depend on? */

	struct list_head target_list;



	/* Who is waiting for us to be unloaded */

	struct task_struct *waiter;



	/* Destruction function. */

	void (*exit)(void);

kernel/module.c

+8 −38
Original line number Diff line number Diff line
@@ -644,8 +644,6 @@ static int module_unload_init(struct module *mod) 


	/* Hold reference count during initialization. */

	__this_cpu_write(mod->refptr->incs, 1);

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

	mod->waiter = current;



	return 0;

}
@@ -771,16 +769,9 @@ static int __try_stop_module(void *_sref) 


static int try_stop_module(struct module *mod, int flags, int *forced)

{

	if (flags & O_NONBLOCK) {

	struct stopref sref = { mod, flags, forced };



	return stop_machine(__try_stop_module, &sref, NULL);

	} else {

		/* We don't need to stop the machine for this. */

		mod->state = MODULE_STATE_GOING;

		synchronize_sched();

		return 0;

	}

}



unsigned long module_refcount(struct module *mod)
@@ -813,21 +804,6 @@ EXPORT_SYMBOL(module_refcount); 
/* This exists whether we can unload or not */

static void free_module(struct module *mod);



static void wait_for_zero_refcount(struct module *mod)

{

	/* Since we might sleep for some time, release the mutex first */

	mutex_unlock(&module_mutex);

	for (;;) {

		pr_debug("Looking at refcount...\n");

		set_current_state(TASK_UNINTERRUPTIBLE);

		if (module_refcount(mod) == 0)

			break;

		schedule();

	}

	current->state = TASK_RUNNING;

	mutex_lock(&module_mutex);

}



SYSCALL_DEFINE2(delete_module, const char __user *, name_user,

		unsigned int, flags)

{
@@ -842,6 +818,11 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user, 
		return -EFAULT;

	name[MODULE_NAME_LEN-1] = '\0';



	if (!(flags & O_NONBLOCK)) {

		printk(KERN_WARNING

		       "waiting module removal not supported: please upgrade");

	}



	if (mutex_lock_interruptible(&module_mutex) != 0)

		return -EINTR;
@@ -859,8 +840,7 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user, 


	/* Doing init or already dying? */

	if (mod->state != MODULE_STATE_LIVE) {

		/* FIXME: if (force), slam module count and wake up

                   waiter --RR */

		/* FIXME: if (force), slam module count damn the torpedoes */

		pr_debug("%s already dying\n", mod->name);

		ret = -EBUSY;

		goto out;
@@ -876,18 +856,11 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user, 
		}

	}



	/* Set this up before setting mod->state */

	mod->waiter = current;



	/* Stop the machine so refcounts can't move and disable module. */

	ret = try_stop_module(mod, flags, &forced);

	if (ret != 0)

		goto out;



	/* Never wait if forced. */

	if (!forced && module_refcount(mod) != 0)

		wait_for_zero_refcount(mod);



	mutex_unlock(&module_mutex);

	/* Final destruction now no one is using it. */

	if (mod->exit != NULL)
@@ -1005,9 +978,6 @@ void module_put(struct module *module) 
		__this_cpu_inc(module->refptr->decs);



		trace_module_put(module, _RET_IP_);

		/* Maybe they're waiting for us to drop reference? */

		if (unlikely(!module_is_live(module)))

			wake_up_process(module->waiter);

		preempt_enable();

	}

}