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From:   Gabriel Krisman Bertazi <krisman@collabora.com>
To:     =?utf-8?Q?Andr=C3=A9?= Almeida <andrealmeid@collabora.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
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Subject: Re: [RFC PATCH 01/13] futex2: Implement wait and wake functions
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 (=?utf-8?Q?=22Andr=C3=A9?=
        Almeida"'s message of "Thu, 18 Feb 2021 10:29:46 -0300")
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        <87k0r9w19l.fsf@collabora.com>
        <74e321d5-2cf5-f3a6-6a7a-49e1ed2fda07@collabora.com>
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Date:   Thu, 18 Feb 2021 10:48:50 -0500
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André Almeida <andrealmeid@collabora.com> writes:

>>> +		if (unlikely(ret)) {
>>> +			spin_unlock(&bucket->lock);
>>> +
>>> +			bucket_dec_waiters(bucket);
>>> +			__set_current_state(TASK_RUNNING);
>>> +			*awakened = futex_dequeue_multiple(futexv, i);
>>> +
>>> +			if (__get_user(uval, uaddr))
>>> +				return -EFAULT;
>>> +
>>> +			if (*awakened >= 0)
>>> +				return 1;
>> If you are awakened, you don't need to waste time with trying to get
>> the
>> next key.
>> 
>
> Yes, and this is what this return is supposed to do. What I'm missing?

you don't need to do that __get_user if some other key was already awoke.

[...]
if (*awakened >= 0)
	return 1;

if (__get_user(uval, uaddr))
	return -EFAULT;
[...]

-- 
Gabriel Krisman Bertazi