linux-kernel - Re: [PATCH] drivers/net/wan/wanxl.c: time_before(timeout, jiffies) -> jiffies, timeout

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Date:	Thu, 20 Mar 2008 14:06:18 -0700
From:	Joe Perches <joe@...ches.com>
To:	Roel Kluin <12o3l@...cali.nl>
Cc:	khc@...waw.pl, lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drivers/net/wan/wanxl.c: time_before(timeout, jiffies)
	-> jiffies, timeout

On Thu, 2008-03-20 at 21:23 +0100, Roel Kluin wrote:
> > -	while ((stat = readl(card->plx + PLX_MAILBOX_0)) != 0) {
> > -		if (time_before(timeout, jiffies)) {
> > -			printk(KERN_WARNING "wanXL %s: timeout waiting for"
> > -			       " PUTS to complete\n", pci_name(pdev));
> > -			wanxl_pci_remove_one(pdev);
> > -			return -ENODEV;
> > -		}
> > -
> > -		switch(stat & 0xC0) {
> > -		case 0x00:	/* hmm - PUTS completed with non-zero code? */
> > -		case 0x80:	/* PUTS still testing the hardware */
> > -			break;
> > -
> > -		default:
> > -			printk(KERN_WARNING "wanXL %s: PUTS test 0x%X"
> > +	if (TEST_UNTIL_TIMEOUT(((stat = readl(card->plx + PLX_MAILBOX_0)) != 0),
> > +			       20 * HZ)) {
> > +		printk(KERN_WARNING "wanXL %s: PUTS test 0x%X"
> >  			       " failed\n", pci_name(pdev), stat & 0x30);
> >  			wanxl_pci_remove_one(pdev);
> >  			return -ENODEV;
> 
> Doesn't this change behavior for (stat & 0xC0) != 0x00 or 0x80?

Probably, I didn't look at it too much.  Feel free to fix it.

The patch was just to demonstrate the statement expression macro
and show the lack of schedules() in some of the loops.

Maybe the statement expression macro should optionally schedule too:

#define TEST_UNTIL_TIMEOUT(test, hz, schedule)		\
({							\
	typeof(test) t;					\
	unsigned long timeout = jiffies + (hz);		\
	do {						\
		t = (test);				\
		if (t)					\
			break;				\
		if ((schedule))				\
			schedule();			\
	} while (time_before(jiffies, timeout));	\
	t;						\
})

cheers, Joe

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