Subject: Re: USB: FIx locks and urb->status in adutux
From: Vitaliy Ivanov <vitalivanov@gmail.com>
Reply-To: vitalivanov@gmail.com
To: Pete Zaitcev <zaitcev@redhat.com>, vitalivanov@gmail.com
Cc: Oliver Neukum <oliver@neukum.org>, linux-usb-devel@lists.sourceforge.net,
       greg@kroah.com, linux-kernel@vger.kernel.org, netwiz@crc.id.au
In-Reply-To: <20071029212433.c9837c4b.zaitcev@redhat.com>
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	 <200710231138.38266.oliver@neukum.org>
	 <20071023185302.5ce9d187.zaitcev@redhat.com>
	 <1193234987.13750.21.camel@dell1.softservecom.com>
	 <20071024202555.4f1cd215.zaitcev@redhat.com>
	 <1193681097.20985.31.camel@dell1.softservecom.com>
	 <20071029212433.c9837c4b.zaitcev@redhat.com>
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Date: Tue, 30 Oct 2007 15:09:54 +0200
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On Tue, 2007-10-30 at 06:24, Pete Zaitcev wrote:

> However, this looks wrong:
> 
> > +			 dev->interrupt_in_endpoint->bInterval);
> > +	dev->read_urb_finished = 0;
> > +	retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
> > +	/* we ignore failure */
> > +	/* end of fixup for first read */
> > +
> > +	/* initialize out direction */
> > +	dev->out_urb_finished = 1;
> 
> The finished flag is only set when URB is not in use anymore. Did you
> observe an anomaly with my code? Any hangs? If so, I assure you this
> is not the fix. As it's written, even if we ignore the failure (e.g.
> do not pass it to userland), we sill have to maintain the correct
> flag state.

As about read_urb_finished probably it's OK. But we shouldn't decrease open_count in the case of error as then we return normal exit value.
Here is what we had before:

				 dev->interrupt_in_endpoint->bInterval);
		dev->read_urb_finished = 0;
		retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
		if (retval) {
			dev->read_urb_finished = 1;
			--dev->open_count;
		}

So I can left it but w/o this line:
--dev->open_count;

What is more critical is that I added:

	/* initialize out direction */
	dev->out_urb_finished = 1;

Without this we'll always have write timeouts.

		Vitaliy

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