linux-kernel - Re: [RFC][PATCH] p54usb: rewriting rx/tx routines to make use of usb

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Message-ID: <493AF2EE.20605@lwfinger.net>
Date:	Sat, 06 Dec 2008 15:47:26 -0600
From:	Larry Finger <Larry.Finger@...inger.net>
To:	Christian Lamparter <chunkeey@....de>
CC:	Greg KH <gregkh@...e.de>, linux-wireless@...r.kernel.org,
	Johannes Berg <johannes@...solutions.net>,
	John W Linville <linville@...driver.com>,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	Alan Stern <stern@...land.harvard.edu>
Subject: Re: [RFC][PATCH] p54usb: rewriting rx/tx routines to make use of
 usb_anchor's facilities

Christian Lamparter wrote:
> 
> Alan, I've got a question about:
> "Create and initialize a usb_anchor structure, and each time you create
> a new URB, call usb_anchor_urb().  Then you can free the URB as soon as
> it is submitted; the anchor will keep it pinned until it completes, and
> it is automatically removed from the anchor when the completion routine
> is called."
> 
> Do we have to call usb_free_urb again, if we're resubmitting the urb in the
> complete callback? (the code what I'm referring to is p54u_rx_cb in p54usb.c)

I am very interested in the answer to this question. My interpretation is that
you cannot resubmit the urb after it has been posted to usb_anchor_usb() because
the USB core will have deleted it, and that the callback routine will have to
allocate a new urb, anchor it, and then free it as well.

Larry
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