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module: remove rmmod --wait option.

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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: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2013-09-17 05:48:51 +09:30
commit 3f2b9c9cdf
2 changed files with 8 additions and 41 deletions
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3
include/linux/module.h
View file

@ -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);

46
kernel/module.c
View file

@ -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 };
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;
}
return stop_machine(__try_stop_module, &sref, NULL);
}
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();
}
}