Re: [PATCH 1/3] wait-simple: Introduce the simple waitqueue implementation

From: Paul Gortmaker
Date: Thu Dec 12 2013 - 09:19:40 EST


On 13-12-12 06:20 AM, Peter Zijlstra wrote:
> On Thu, Dec 12, 2013 at 12:18:09PM +0100, Peter Zijlstra wrote:
>> On Wed, Dec 11, 2013 at 08:06:37PM -0500, Paul Gortmaker wrote:

[...]

>>> +
>>> +unsigned int
>>> +__swake_up(struct swait_queue_head *head, unsigned int state, unsigned int num)
>>> +{
>>> + unsigned long flags;
>>> + int woken;
>>> +
>>> + if (!swaitqueue_active(head))
>>> + return 0;
>>> +
>>> + raw_spin_lock_irqsave(&head->lock, flags);
>>> + woken = __swake_up_locked(head, state, num);
>>> + raw_spin_unlock_irqrestore(&head->lock, flags);
>>> + return woken;
>>> +}
>>> +EXPORT_SYMBOL(__swake_up);
>>
>> Urgh, fail. Do not put unbounded loops in raw_spin_lock.
>>
>> I think I posted a patch a while back to cure this.
>
> tada!
>
> lkml.kernel.org/r/20131004145625.GN3081@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Yep, I linked to that at the bottom of the 0/3 -- I was still
hoping we could find a way to somehow do that w/o passing
the flags around between functions... perhaps it isn't possible...
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