Re: [patch 04/12] block/xd: replace schedule_timeout() with msleep()

["Maciej W. Rozycki" <macro@linux-mips.org>]

On Mon, 20 Jun 2005 domen@coderock.org wrote:

> From: Nishanth Aravamudan <nacc@us.ibm.com>
> 
> 
> 
> Use msleep() instead of schedule_timeout() to guarantee the task
> delays as expected. The current code wishes to sleep for 1 jiffy, but I am not
> sure if this is actually intended, as with the change to HZ=1000, the time
> equivalent of 1 jiffy changed from 10ms to 1ms. I have assumed the former in
> this case; however the patch can be easily changed to assume the latter.
[...]
> @@ -529,10 +530,8 @@ static inline u_char xd_waitport (u_shor
>  	int success;
>  
>  	xdc_busy = 1;
> -	while ((success = ((inb(port) & mask) != flags)) && time_before(jiffies, expiry)) {
> -		set_current_state(TASK_UNINTERRUPTIBLE);
> -		schedule_timeout(1);
> -	}
> +	while ((success = ((inb(port) & mask) != flags)) && time_before(jiffies, expiry))
> +		msleep(10);
>  	xdc_busy = 0;
>  	return (success);
>  }

 I think it's obvious what this code intends and this makes the function 
to busy-loop instead of giving up the CPU friendly.  The change makes no 
sense -- the code is correct as is.

 Maciej
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