From mboxrd@z Thu Jan  1 00:00:00 1970
From: greg@kroah.com (Greg KH)
Date: Tue, 5 Jul 2011 06:34:40 -0700
Subject: read / write / close sync for device files
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References: <BANLkTimbOTU8JBQaPaaVuY1PNw317KasvQ@mail.gmail.com>
	<20110704161045.GB18303@kroah.com>
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To: kernelnewbies@lists.kernelnewbies.org
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On Tue, Jul 05, 2011 at 12:37:26PM +0530, Amit Nagal wrote:
> so do the usb-core layers or VFS layers maintains some locks that take
> care that if read / write is in progress
> and application calls close() , corresponding release() method in usb
> driver will be called only upon completion
> of all read / writes ?

No, release will be called when all of the userspace file handles call
close(), and not before.

hope this helps,

greg k-h