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author | Peter Zijlstra <peterz@infradead.org> | 2015-02-11 15:01:13 +1030 |
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committer | Rusty Russell <rusty@rustcorp.com.au> | 2015-02-11 15:02:04 +1030 |
commit | 9cc019b8c94fa59e02fd82f15f7b7d689e35c190 (patch) | |
tree | 0d6775b29012dd6a2df95cb16bd190faffd44780 /kernel | |
parent | d64810f56147b53e92228c31442e925576314aa2 (diff) | |
download | linux-stable-9cc019b8c94fa59e02fd82f15f7b7d689e35c190.tar.gz linux-stable-9cc019b8c94fa59e02fd82f15f7b7d689e35c190.tar.bz2 linux-stable-9cc019b8c94fa59e02fd82f15f7b7d689e35c190.zip |
module: Replace over-engineered nested sleep
Since the introduction of the nested sleep warning; we've established
that the occasional sleep inside a wait_event() is fine.
wait_event() loops are invariant wrt. spurious wakeups, and the
occasional sleep has a similar effect on them. As long as its occasional
its harmless.
Therefore replace the 'correct' but verbose wait_woken() thing with
a simple annotation to shut up the warning.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/module.c | 36 |
1 files changed, 8 insertions, 28 deletions
diff --git a/kernel/module.c b/kernel/module.c index d7a92682fba3..82dc1f899e6d 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2984,6 +2984,12 @@ static bool finished_loading(const char *name) struct module *mod; bool ret; + /* + * The module_mutex should not be a heavily contended lock; + * if we get the occasional sleep here, we'll go an extra iteration + * in the wait_event_interruptible(), which is harmless. + */ + sched_annotate_sleep(); mutex_lock(&module_mutex); mod = find_module_all(name, strlen(name), true); ret = !mod || mod->state == MODULE_STATE_LIVE @@ -3126,32 +3132,6 @@ static int may_init_module(void) } /* - * Can't use wait_event_interruptible() because our condition - * 'finished_loading()' contains a blocking primitive itself (mutex_lock). - */ -static int wait_finished_loading(struct module *mod) -{ - DEFINE_WAIT_FUNC(wait, woken_wake_function); - int ret = 0; - - add_wait_queue(&module_wq, &wait); - for (;;) { - if (finished_loading(mod->name)) - break; - - if (signal_pending(current)) { - ret = -ERESTARTSYS; - break; - } - - wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); - } - remove_wait_queue(&module_wq, &wait); - - return ret; -} - -/* * We try to place it in the list now to make sure it's unique before * we dedicate too many resources. In particular, temporary percpu * memory exhaustion. @@ -3171,8 +3151,8 @@ again: || old->state == MODULE_STATE_UNFORMED) { /* Wait in case it fails to load. */ mutex_unlock(&module_mutex); - - err = wait_finished_loading(mod); + err = wait_event_interruptible(module_wq, + finished_loading(mod->name)); if (err) goto out_unlocked; goto again; |