linux-kernel - Re: [PATCH] rtc: remove BKL for ioctl()

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Message-ID: <20080625233017.5b207e94@lxorguk.ukuu.org.uk>
Date:	Wed, 25 Jun 2008 23:30:17 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Jonathan Corbet <corbet@....net>
Cc:	David Brownell <david-b@...bell.net>,
	lkml <linux-kernel@...r.kernel.org>, rtc-linux@...glegroups.com
Subject: Re: [PATCH] rtc: remove BKL for ioctl()

On Wed, 25 Jun 2008 16:39:28 -0600
Jonathan Corbet <corbet@....net> wrote:

> On Sun, 22 Jun 2008 19:55:42 -0700
> David Brownell <david-b@...bell.net> wrote:
> 
> > Remove implicit use of BKL in ioctl() from the RTC framework.
> 
> Looks good, I'll happily put it into the bkl-removal tree.  One
> question, though:
> 
> > +	err = mutex_lock_interruptible(&rtc->ops_lock);
> > +	if (err)
> > +		return -EBUSY;
> > +
> 
> Shouldn't that be -EINTR?

For an ioctl case which should never be blocking for long periods it
shouldn't be _interruptible in the first place, that will just introduce
bizarre and weird bugs in application code.

If there are slow ops they should drop and retake the lock.

Alan
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