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modules: Replace synchronize_sched() and call_rcu_sched() 

Now that synchronize_rcu() waits for preempt-disable regions of code
as well as RCU read-side critical sections, synchronize_sched() can
be replaced by synchronize_rcu().  Similarly, call_rcu_sched() can be
replaced by call_rcu().  This commit therefore makes these changes.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Acked-by: Jessica Yu <jeyu@kernel.org>
This commit is contained in:
Paul E. McKenney 2018-11-06 19:17:01 -08:00
parent c9a863bbb1
commit cb2f55369d
1 changed files with 7 additions and 7 deletions
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14
kernel/module.c
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@ -2159,7 +2159,7 @@ static void free_module(struct module *mod)
/* Remove this module from bug list, this uses list_del_rcu */
module_bug_cleanup(mod);
/* Wait for RCU-sched synchronizing before releasing mod->list and buglist. */
synchronize_sched();
synchronize_rcu();
mutex_unlock(&module_mutex);
/* This may be empty, but that's OK */
@ -3507,15 +3507,15 @@ static noinline int do_init_module(struct module *mod)
/*
* We want to free module_init, but be aware that kallsyms may be
* walking this with preempt disabled. In all the failure paths, we
* call synchronize_sched(), but we don't want to slow down the success
* call synchronize_rcu(), but we don't want to slow down the success
* path, so use actual RCU here.
* Note that module_alloc() on most architectures creates W+X page
* mappings which won't be cleaned up until do_free_init() runs. Any
* code such as mark_rodata_ro() which depends on those mappings to
* be cleaned up needs to sync with the queued work - ie
* rcu_barrier_sched()
* rcu_barrier()
*/
call_rcu_sched(&freeinit->rcu, do_free_init);
call_rcu(&freeinit->rcu, do_free_init);
mutex_unlock(&module_mutex);
wake_up_all(&module_wq);
@ -3526,7 +3526,7 @@ fail_free_freeinit:
fail:
/* Try to protect us from buggy refcounters. */
mod->state = MODULE_STATE_GOING;
synchronize_sched();
synchronize_rcu();
module_put(mod);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
@ -3819,7 +3819,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
ddebug_cleanup:
ftrace_release_mod(mod);
dynamic_debug_remove(mod, info->debug);
synchronize_sched();
synchronize_rcu();
kfree(mod->args);
free_arch_cleanup:
module_arch_cleanup(mod);
@ -3834,7 +3834,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
mod_tree_remove(mod);
wake_up_all(&module_wq);
/* Wait for RCU-sched synchronizing before releasing mod->list. */
synchronize_sched();
synchronize_rcu();
mutex_unlock(&module_mutex);
free_module:
/* Free lock-classes; relies on the preceding sync_rcu() */