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module: Unlink module with RCU synchronizing instead of stop_machine

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Unlink module from module list with RCU synchronizing instead
of using stop_machine(). Since module list is already protected
by rcu, we don't need stop_machine() anymore.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Masami Hiramatsu 2014-11-10 09:27:29 +10:30 committed by Rusty Russell
parent 4f48795b61
commit 461e34aed0
1 changed files with 5 additions and 13 deletions
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18
kernel/module.c
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@ -1697,18 +1697,6 @@ static void mod_sysfs_teardown(struct module *mod)
mod_sysfs_fini(mod);
}
/*
* unlink the module with the whole machine is stopped with interrupts off
* - this defends against kallsyms not taking locks
*/
static int __unlink_module(void *_mod)
{
struct module *mod = _mod;
list_del(&mod->list);
module_bug_cleanup(mod);
return 0;
}
#ifdef CONFIG_DEBUG_SET_MODULE_RONX
/*
* LKM RO/NX protection: protect module's text/ro-data
@ -1860,7 +1848,11 @@ static void free_module(struct module *mod)
/* Now we can delete it from the lists */
mutex_lock(&module_mutex);
stop_machine(__unlink_module, mod, NULL);
/* Unlink carefully: kallsyms could be walking list. */
list_del_rcu(&mod->list);
/* Wait for RCU synchronizing before releasing mod->list. */
synchronize_rcu();
module_bug_cleanup(mod);
mutex_unlock(&module_mutex);
/* This may be NULL, but that's OK */