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module: wait for dependent modules doing init.

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There have been reports of modules failing to load because the modules
they depend on are still loading.  This changes the modules to wait
for a reasonable length of time in that case.  We time out eventually,
because there can be module loops or broken modules.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2008-01-29 17:13:18 -05:00
parent a2da4052f1
commit c9a3ba55bb
1 changed files with 23 additions and 5 deletions
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28
kernel/module.c
View File

@ -65,6 +65,9 @@
static DEFINE_MUTEX(module_mutex);
static LIST_HEAD(modules);
/* Waiting for a module to finish initializing? */
static DECLARE_WAIT_QUEUE_HEAD(module_wq);
static BLOCKING_NOTIFIER_HEAD(module_notify_list);
int register_module_notifier(struct notifier_block * nb)
@ -84,8 +87,11 @@ EXPORT_SYMBOL(unregister_module_notifier);
static inline int strong_try_module_get(struct module *mod)
{
if (mod && mod->state == MODULE_STATE_COMING)
return -EBUSY;
if (try_module_get(mod))
return 0;
return try_module_get(mod);
else
return -ENOENT;
}
static inline void add_taint_module(struct module *mod, unsigned flag)
@ -539,11 +545,21 @@ static int already_uses(struct module *a, struct module *b)
static int use_module(struct module *a, struct module *b)
{
struct module_use *use;
int no_warn;
int no_warn, err;
if (b == NULL || already_uses(a, b)) return 1;
if (!strong_try_module_get(b))
/* If we're interrupted or time out, we fail. */
if (wait_event_interruptible_timeout(
module_wq, (err = strong_try_module_get(b)) != -EBUSY,
30 * HZ) <= 0) {
printk("%s: gave up waiting for init of module %s.\n",
a->name, b->name);
return 0;
}
/* If strong_try_module_get() returned a different error, we fail. */
if (err)
return 0;
DEBUGP("Allocating new usage for %s.\n", a->name);
@ -816,7 +832,7 @@ static inline void module_unload_free(struct module *mod)
static inline int use_module(struct module *a, struct module *b)
{
return strong_try_module_get(b);
return strong_try_module_get(b) == 0;
}
static inline void module_unload_init(struct module *mod)
@ -1326,7 +1342,7 @@ void *__symbol_get(const char *symbol)
preempt_disable();
value = __find_symbol(symbol, &owner, &crc, 1);
if (value && !strong_try_module_get(owner))
if (value && strong_try_module_get(owner) != 0)
value = 0;
preempt_enable();
@ -2132,6 +2148,7 @@ sys_init_module(void __user *umod,
mutex_lock(&module_mutex);
free_module(mod);
mutex_unlock(&module_mutex);
wake_up(&module_wq);
return ret;
}
@ -2146,6 +2163,7 @@ sys_init_module(void __user *umod,
mod->init_size = 0;
mod->init_text_size = 0;
mutex_unlock(&module_mutex);
wake_up(&module_wq);
return 0;
}