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Date: Sat, 6 Jan 2007 15:38:18 +0100 (MET)
From: Jan Engelhardt <jengelh@linux01.gwdg.de>
To: David Rientjes <rientjes@cs.washington.edu>
cc: "Ahmed S. Darwish" <darwish.07@gmail.com>, alan@lxorguk.ukuu.org.uk,
       linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2.6.20-rc3] TTY_IO code cleanups
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On Jan 5 2007 16:00, David Rientjes wrote:
>> @@ -791,17 +790,15 @@ static int tty_ldisc_try(struct tty_struct *tty)
>>  {
>>  	unsigned long flags;
>>  	struct tty_ldisc *ld;
>> -	int ret = 0;
>>  	
>>  	spin_lock_irqsave(&tty_ldisc_lock, flags);
>>  	ld = &tty->ldisc;
>> -	if(test_bit(TTY_LDISC, &tty->flags))
>> -	{
>> +	if(test_bit(TTY_LDISC, &tty->flags)) {
>>  		ld->refcount++;
>> -		ret = 1;
>> +		return 1;
>>  	}
>>  	spin_unlock_irqrestore(&tty_ldisc_lock, flags);
>> -	return ret;
>> +	return 0;
>>  }
>>  
>>  /**
>
>You leave tty_ldisk_lock locked.

Hence it was not redundant. Either way,

if(test_bit(...)) {
   spin_unlock_irqrestore(..)
   return 1;
}

would probably generate the same ASM as the original, hence it is not
really an improvement.


	-`J'
--