Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758553AbYH0QYY (ORCPT ); Wed, 27 Aug 2008 12:24:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755424AbYH0QX7 (ORCPT ); Wed, 27 Aug 2008 12:23:59 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:33062 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755094AbYH0QX6 (ORCPT ); Wed, 27 Aug 2008 12:23:58 -0400 Date: Wed, 27 Aug 2008 09:08:54 -0700 From: Greg KH To: Oliver Neukum Cc: linux-usb@vger.kernel.org, Stefan Kopp , Marcel Janssen , Felipe Balbi , linux-kernel@vger.kernel.org Subject: Re: [PATCH] USB: add USB test and measurement class driver Message-ID: <20080827160854.GC19710@kroah.com> References: <20080827000501.GA29570@kroah.com> <200808271013.07561.oliver@neukum.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <200808271013.07561.oliver@neukum.org> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2233 Lines: 58 On Wed, Aug 27, 2008 at 10:13:06AM +0200, Oliver Neukum wrote: > Am Mittwoch 27 August 2008 02:05:01 schrieb Greg KH: > > +static ssize_t usbtmc_read(struct file *filp, char __user *buf, > > +??????????????????????? ? size_t count, loff_t *f_pos) > > +{ > > +???????struct usbtmc_device_data *data; > > +???????struct device *dev; > > +???????unsigned long int n_characters; > > +???????u8 *buffer; > > +???????int actual; > > +???????int done; > > +???????int remaining; > > +???????int retval; > > +???????int this_part; > > + > > +???????/* Get pointer to private data structure */ > > +???????data = filp->private_data; > > +???????dev = &data->intf->dev; > > +???????buffer = data->buffer; > > + > > +???????remaining = count; > > +???????done = 0; > > + > > +???????while (remaining > 0) { > > +???????????????if (remaining > USBTMC_SIZE_IOBUFFER - 12 - 3) > > +???????????????????????this_part = USBTMC_SIZE_IOBUFFER - 12 - 3; > > +???????????????else > > +???????????????????????this_part = remaining; > > + > > +???????????????/* Setup IO buffer for DEV_DEP_MSG_IN message > > +??????????????? * Refer to class specs for details > > +??????????????? */ > > +???????????????buffer[0] = 2; > > +???????????????buffer[1] = data->bTag; > > +???????????????buffer[2] = ~(data->bTag); > > +???????????????buffer[3] = 0; /* Reserved */ > > +???????????????buffer[4] = (this_part - 12 - 3) & 255; > > +???????????????buffer[5] = ((this_part - 12 - 3) >> 8) & 255; > > +???????????????buffer[6] = ((this_part - 12 - 3) >> 16) & 255; > > +???????????????buffer[7] = ((this_part - 12 - 3) >> 24) & 255; > > +???????????????buffer[8] = data->TermCharEnabled * 2; > > +???????????????/* Use term character? */ > > +???????????????buffer[9] = data->TermChar; > > +???????????????buffer[10] = 0; /* Reserved */ > > +???????????????buffer[11] = 0; /* Reserved */ > > This function will go bad if concurrent readers enter, yet it has no locking. Now fixed with an i/o mutex. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/