Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753891Ab0KUOOI (ORCPT ); Sun, 21 Nov 2010 09:14:08 -0500 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:53235 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753484Ab0KUOOG (ORCPT ); Sun, 21 Nov 2010 09:14:06 -0500 Date: Sun, 21 Nov 2010 14:12:26 +0000 From: Alan Cox To: Rodolfo Giometti Cc: Alexander Gordeev , linux-kernel@vger.kernel.org, "Nikita V. Youshchenko" , linuxpps@ml.enneenne.com, Greg Kroah-Hartman , Andrew Morton , Tejun Heo Subject: Re: [PATCHv4 05/17] pps: access pps device by direct pointer Message-ID: <20101121141226.1576758b@lxorguk.ukuu.org.uk> In-Reply-To: <20101120154416.GX13356@enneenne.com> References: <57dad12253191b67a6a08bb9c464bd54e70e52a3.1290087479.git.lasaine@lvk.cs.msu.su> <20101120154416.GX13356@enneenne.com> X-Mailer: Claws Mail 3.7.6 (GTK+ 2.18.9; x86_64-redhat-linux-gnu) Face: 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 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 773 Lines: 23 > Maybe this lock is useless... however, are we sure that before setting > tty->disc_data to pps its value is null? Otherwise the dcd_change may > be called with an oops! We cannot control serial port IRQ > generation... :-/ tty->disc_data is LDISC private. It may be any arbitary value on entry to the ldisc open method. > > + spin_lock_irq(&pps_ldisc_lock); > > + tty->disc_data = NULL; > > + spin_unlock_irq(&pps_ldisc_lock); And you don't need to set it to NULL after - some ldiscs do this mostly as a debug aid. Alan -- 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/